ci: Consistently use dashes in job/stage names

We currently have a mix of dashes and underscores, with the former
being predominantly used by newer jobs, so settle on that.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/430>

.gitlab-ci.yml

@@ -16,7 +16,7 @@ include:
       tarball-artifact-path: "$TARBALL_ARTIFACT_PATH"
 
 stages:
-  - pre_review
+  - pre-review
   - prepare
   - review
   - build
@@ -30,7 +30,7 @@ variables:
   MESON_BUILD_DIR: build
   TARBALL_ARTIFACT_PATH: "${MESON_BUILD_DIR}/meson-dist/${CI_PROJECT_NAME}-${CI_COMMIT_TAG}.tar.xz"
 
-.pipeline_guard: &pipeline_guard
+.pipeline-guard: &pipeline_guard
   rules:
     - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
     - if: '$CI_COMMIT_TAG'
@@ -38,15 +38,15 @@ variables:
     - if: '$CI_COMMIT_BRANCH =~ /^gnome-[0-9-]+$/'
     - when: 'manual'
 
-.prereview_req: &prereview_req
+.prereview-req: &prereview_req
   needs:
-    - check_commit_log
+    - check-commit-log
     - check-merge-request
 
-check_commit_log:
+check-commit-log:
   extends:
     - .fdo.ci-fairy
-  stage: pre_review
+  stage: pre-review
   script:
     - if [[ x"$CI_MERGE_REQUEST_TARGET_BRANCH_NAME" != "x" ]] ;
       then
@@ -65,7 +65,7 @@ check_commit_log:
 check-merge-request:
   extends:
     - .fdo.ci-fairy
-  stage: pre_review
+  stage: pre-review
   script:
     - if [[ x"$CI_MERGE_REQUEST_TARGET_BRANCH_NAME" != "x" ]] ;
       then
@@ -82,14 +82,14 @@ check-merge-request:
       junit: check-merge-request-report.xml
 
 check-reuse:
-  stage: pre_review
+  stage: pre-review
   image:
     name: fsfe/reuse:latest
     entrypoint: [""]
   script:
     - reuse lint
 
-js_check:
+js-check:
   stage: review
   <<: *prereview_req
   script:
@@ -106,7 +106,7 @@ eslint:
     reports:
       junit: "$LINT_LOG"
 
-potfile_js_check:
+potfile-js-check:
   stage: review
   <<: *prereview_req
   script: