ghcup-metadata: Fix date modifier (M = minutes, m = month)

Fixes #23552

.gitlab-ci.yml

@@ -1063,7 +1063,7 @@ ghcup-metadata-nightly:
       artifacts: false
     - job: project-version
   script:
-    - nix shell --extra-experimental-features nix-command -f .gitlab/rel_eng -c ghcup-metadata --metadata ghcup-0.0.7.yaml --date="$(date -d $CI_PIPELINE_CREATED_AT +%Y-%M-%d)" --pipeline-id="$CI_PIPELINE_ID" --version="$ProjectVersion" > "metadata_test.yaml"
+    - nix shell --extra-experimental-features nix-command -f .gitlab/rel_eng -c ghcup-metadata --metadata ghcup-0.0.7.yaml --date="$(date -d $CI_PIPELINE_CREATED_AT +%Y-%m-%d)" --pipeline-id="$CI_PIPELINE_ID" --version="$ProjectVersion" > "metadata_test.yaml"
   rules:
     - if: $NIGHTLY
 
@@ -1100,7 +1100,7 @@ ghcup-metadata-release:
   # No explicit needs for release pipeline as we assume we need everything and everything will pass.
   extends: .ghcup-metadata
   script:
-    - nix shell --extra-experimental-features nix-command -f .gitlab/rel_eng -c ghcup-metadata --release-mode --metadata ghcup-0.0.7.yaml --date="$(date -d $CI_PIPELINE_CREATED_AT +%Y-%M-%d)" --pipeline-id="$CI_PIPELINE_ID" --version="$ProjectVersion" > "metadata_test.yaml"
+    - nix shell --extra-experimental-features nix-command -f .gitlab/rel_eng -c ghcup-metadata --release-mode --metadata ghcup-0.0.7.yaml --date="$(date -d $CI_PIPELINE_CREATED_AT +%Y-%m-%d)" --pipeline-id="$CI_PIPELINE_ID" --version="$ProjectVersion" > "metadata_test.yaml"
   rules:
     - if: '$RELEASE_JOB == "yes"'