fix: manually install shfmt for jobs in common-ci-tasks

This allows us to publish an image for other projects to use

.gitlab-ci.yml

@@ -78,3 +78,9 @@ container_image_tagged:
     - .container_builds
   rules:
     - if: "$CI_COMMIT_TAG"
+
+# Override default shfmt so we can publish the image
+shfmt:
+  image: golang:1.23
+  before_script:
+    - go install mvdan.cc/sh/v3/cmd/shfmt@v${GL_ASDF_SHFMT_VERSION}