Minor YAML fixes (#502)

Author: vkucera

.github/dependabot.yml

@@ -1,3 +1,4 @@
+---
 # Dependabot configuration
 # Reference: https://docs.github.com/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
 

.github/workflows/clang-format-lint.yml

@@ -59,7 +59,7 @@ jobs:
           delete-branch: true
       - name: Create PR output
         if: steps.clang-result.outputs.status == 1
-        run: |
+        run: |-
           echo "::error::Files need formatting."
           if [ ${{ github.event_name }} == 'push' ]; then
             echo "::error::Merge pull request ${{ steps.cpr.outputs.pull-request-url }} to apply automatic fixes."

.github/workflows/space-checker.yml

@@ -15,7 +15,7 @@ jobs:
         with:
           fetch-depth: 0 # needed to get the full history
       - name: Find bad spacing
-        run: |
+        run: |-
           # Find tabs and trailing whitespaces in modified text files and show where they are
           status_tab=0
           status_trail=0