Add changelog enforcement stuff

.github/dependabot.yml

@@ -4,7 +4,15 @@ updates:
     directory: "/"
     schedule:
       interval: "daily"
+    labels:
+      - "dependencies"
+      - "github-actions"
+      - "no changelog entry needed"
   - package-ecosystem: "cargo"
     directory: "/"
     schedule:
       interval: "daily"
+    labels:
+      - "dependencies"
+      - "rust"
+      - "no changelog entry needed"

.github/pull_request_template.md

@@ -0,0 +1,4 @@
+
+Pull request checklist:
+
+- [ ] `CHANGELOG.md` was updated, if applicable

.github/workflows/changelog-check.yml

@@ -0,0 +1,19 @@
+name: Changelog Check
+
+on:
+  pull_request:
+    branches: [ master ]
+    types: [ opened, synchronize, reopened, ready_for_review, labeled, unlabeled ]
+
+jobs:
+  check-changelog:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      # Gives an error if there's no change in the changelog (except using label)
+      - name: Changelog check
+        uses: dangoslen/changelog-enforcer@v1.5.1
+        with:
+          changeLogPath: 'CHANGELOG.md'
+          skipLabel: 'no changelog entry needed'