.gitlab-ci.yml: Correctly upgrade `meson`.
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a0774b7..a6f75d6 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -47,7 +47,7 @@
     - Import-Certificate -CertStoreLocation "Cert:\LocalMachine\Root" "C:\roots.sst"
     # Make sure meson is up to date so we don't need to rebuild the image
     # with each release.
-    - pip3 install 'meson==0.59.*'
+    - pip3 install -U 'meson==0.59.*'
     - pip3 install --upgrade certifi
     - pip3 install -U ninja