feat: run mise to validate .tool-versions

Part of https://gitlab.com/gitlab-com/runbooks/-/issues/134, start
validating .tool-versions against mise.

asdf-tool-versions.md

 # [`asdf-tool-versions`](./asdf-tool-versions.yml)
-Checks that the `.tool-versions` file is synced with .gitlab-ci-asdf-versions.yml, that all the plugins are declared in `./scripts/install-asdf-plugins.sh` and that ASDF is generally working.
+Checks that the `.tool-versions` file is synced with .gitlab-ci-asdf-versions.yml, that all the plugins are declared in `./scripts/install-asdf-plugins.sh` and that ASDF and Mise are generally working.
 * Default Stages: `validate`
@@ -21,9 +21,12 @@ include:
   # Checks that the `.tool-versions` file is synced with .gitlab-ci-asdf-versions.yml,
   # that all the plugins are declared in `./scripts/install-asdf-plugins.sh`
-  # and that ASDF is generally working
+  # and that asdf and mise are generally working
   # see https://gitlab.com/gitlab-com/gl-infra/common-ci-tasks/-/blob/main/asdf-tool-versions.md
   - project: 'gitlab-com/gl-infra/common-ci-tasks'
     ref: v2.13.0  # renovate:managed
     file: asdf-tool-versions.yml
 ```
+
+Note that during the [Infrastructure group migration from asdf to mise](https://gitlab.com/gitlab-com/runbooks/-/issues/134), two jobs are executed,
+one for `asdf`: `validate_asdf_tool_versions` and a second job for `mise`: `validate_mise_tool_versions`.

asdf-tool-versions.yml

@@ -53,3 +53,49 @@ validate_asdf_tool_versions:
     max: 2
     when:
       - runner_system_failure
+
+validate_mise_tool_versions:
+  stage: $[[ inputs.stage ]]
+  image:
+    name: registry.gitlab.com/gitlab-com/gl-infra/common-ci-tasks/mise:v2.13.0
+    entrypoint: [""]
+  needs: []
+  script:
+    # Handle the VALIDATE_ASDF_TOOL_VERSIONS_DEPLOY_KEY_FILE token if it exists...
+    # Note: This script is identical to the one in renovate-bot.yml
+    - if [[ -n "${VALIDATE_ASDF_TOOL_VERSIONS_DEPLOY_KEY_FILE}" ]]; then
+      eval $(ssh-agent -s);
+      chmod 0600 "$VALIDATE_ASDF_TOOL_VERSIONS_DEPLOY_KEY_FILE";
+      ssh-add "$VALIDATE_ASDF_TOOL_VERSIONS_DEPLOY_KEY_FILE";
+      mkdir -p ~/.ssh;
+      chmod 700 ~/.ssh;
+      ssh-keyscan gitlab.com >> ~/.ssh/known_hosts;
+      ssh -T git@gitlab.com || true;
+      fi
+    - ./scripts/install-asdf-plugins.sh
+    - ./scripts/update-asdf-version-variables.sh
+    - git diff --exit-code
+  after_script: |
+    cat <<-EOD
+    ----------------------------------------------------------
+    Need help? Documentation on the validate_mise_tool_versions CI job can be found at:
+    https://gitlab.com/gitlab-com/gl-infra/common-ci-tasks/-/blob/main/asdf-tool-versions.md
+    EOD
+  rules:
+    # This script can be quite slow (mostly due to the ruby install)
+    # so we only run it when there have been changes
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event" || ($CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH && $CI_PIPELINE_SOURCE != "schedule")'
+      changes:
+        - scripts/install-asdf-plugins.sh
+        - scripts/update-asdf-version-variables.sh
+        - go.mod
+        - .tool-versions
+        - .ruby-version
+        - .gitlab-ci-asdf-versions.yml
+        - .mise.toml
+
+  # Automatically retry on any system blips
+  retry:
+    max: 2
+    when:
+      - runner_system_failure