Use `.json` extension for emscripten-releases-tags.json. NFC (#870)

diff --git a/emscripten-releases-tags.txt b/emscripten-releases-tags.json
similarity index 100%
rename from emscripten-releases-tags.txt
rename to emscripten-releases-tags.json
diff --git a/emsdk.py b/emsdk.py
index 7eea73d..0918fb6 100644
--- a/emsdk.py
+++ b/emsdk.py
@@ -2315,10 +2315,10 @@
 def load_releases_info():
   if not hasattr(load_releases_info, 'cached_info'):
     try:
-      text = open(sdk_path('emscripten-releases-tags.txt'), 'r').read()
+      text = open(sdk_path('emscripten-releases-tags.json'), 'r').read()
       load_releases_info.cached_info = json.loads(text)
     except Exception as e:
-      print('Error parsing emscripten-releases-tags.txt!')
+      print('Error parsing emscripten-releases-tags.json!')
       exit_with_error(str(e))
 
   return load_releases_info.cached_info
diff --git a/scripts/create_release.py b/scripts/create_release.py
index 304ccc9..01bf130 100755
--- a/scripts/create_release.py
+++ b/scripts/create_release.py
@@ -44,7 +44,7 @@
   release_info['releases'] = OrderedDict(reversed(releases))
   release_info['aliases']['latest'] = new_version
 
-  with open(os.path.join(root_dir, 'emscripten-releases-tags.txt'), 'w') as f:
+  with open(os.path.join(root_dir, 'emscripten-releases-tags.json'), 'w') as f:
     f.write(json.dumps(release_info, indent=2))
     f.write('\n')
 
diff --git a/scripts/update_bazel_workspace.sh b/scripts/update_bazel_workspace.sh
index b9b7bd2..42aaab7 100755
--- a/scripts/update_bazel_workspace.sh
+++ b/scripts/update_bazel_workspace.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 # This script will update emsdk/bazel/WORKSPACE to the latest version of
-# emscripten. It reads emsdk/emscripten-releases-tags.txt to get the latest
+# emscripten. It reads emsdk/emscripten-releases-tags.json to get the latest
 # version number. Then, it downloads the prebuilts for that version and computes
 # the sha256sum for the archive. It then puts all this information into the
 # emsdk/bazel/WORKSPACE file.
@@ -12,8 +12,8 @@
 # If the previous command succeeded. We are in the emsdk root. Check to make
 # sure the files and directories we need are present.
 if [[ $? = 0 ]]; then
-  if [[ ! -f emscripten-releases-tags.txt ]]; then
-    echo "Cannot find emscripten-releases-tags.txt."
+  if [[ ! -f emscripten-releases-tags.json ]]; then
+    echo "Cannot find emscripten-releases-tags.json."
     ERR=1
   fi
 
@@ -38,7 +38,7 @@
 
 # Get commit hash for $1 version
 get_hash () {
-  echo $(grep "$1" emscripten-releases-tags.txt | grep -v latest | cut -f4 -d\")
+  echo $(grep "$1" emscripten-releases-tags.json | grep -v latest | cut -f4 -d\")
 }
 
 # Get sha256 for $1 os $2 hash
@@ -62,9 +62,9 @@
   sed -i "5 i $(revisions_item $1)" bazel/revisions.bzl
 }
 
-# Get the latest version number from emscripten-releases-tag.txt.
+# Get the latest version number from emscripten-releases-tag.json.
 VER=$(grep -oP '(?<=latest\": \")([\d\.]+)(?=\")' \
-        emscripten-releases-tags.txt \
+        emscripten-releases-tags.json \
       | sed --expression "s/\./\\\./g")
 
 append_revision ${VER}
diff --git a/test/test.py b/test/test.py
index 5848afd..8f37570 100755
--- a/test/test.py
+++ b/test/test.py
@@ -81,7 +81,7 @@
 
 # Set up
 
-TAGS = json.loads(open('emscripten-releases-tags.txt').read())
+TAGS = json.loads(open('emscripten-releases-tags.json').read())
 
 # Tests
 
diff --git a/test/test_bazel.sh b/test/test_bazel.sh
index 932f55d..1fe58bd 100755
--- a/test/test_bazel.sh
+++ b/test/test_bazel.sh
@@ -5,12 +5,12 @@
 set -x
 set -e
 
-# Get the latest version number from emscripten-releases-tag.txt.
+# Get the latest version number from emscripten-releases-tag.json.
 VER=$(grep -oP '(?<=latest\": \")([\d\.]+)(?=\")' \
-        emscripten-releases-tags.txt \
+        emscripten-releases-tags.json \
       | sed --expression "s/\./\\\./g")
 # Based on the latest version number, get the commit hash for that version.
-HASH=$(grep "\"${VER}\"" emscripten-releases-tags.txt \
+HASH=$(grep "\"${VER}\"" emscripten-releases-tags.json \
       | grep -v latest \
       | cut -f4 -d\")
 
diff --git a/test/test_bazel_mac.sh b/test/test_bazel_mac.sh
index 7ff41cc..0a26a0c 100755
--- a/test/test_bazel_mac.sh
+++ b/test/test_bazel_mac.sh
@@ -5,12 +5,12 @@
 set -x
 set -e
 
-# Get the latest version number from emscripten-releases-tag.txt.
+# Get the latest version number from emscripten-releases-tag.json.
 VER=$(ggrep -oP '(?<=latest\": \")([\d\.]+)(?=\")' \
-        emscripten-releases-tags.txt \
+        emscripten-releases-tags.json \
       | sed "s/\./\\\./g")
 # Based on the latest version number, get the commit hash for that version.
-HASH=$(grep "\"${VER}\"" emscripten-releases-tags.txt \
+HASH=$(grep "\"${VER}\"" emscripten-releases-tags.json \
       | grep -v latest \
       | cut -f4 -d\")