Merge pull request #3500 from inductor/fix_githubactions

Fix GitHub Actions error

.github/workflows/gibberish.txt

@@ -52,3 +52,4 @@ gg
 pqBpw
 JDBC
 JDK
+ForgeGradle

.github/workflows/spellcheck.yaml

@@ -11,4 +11,4 @@ jobs:
     - name: actions/checkout
       uses: actions/checkout@v2
     - name: rojopolis/spellcheck - actually doing something
-      uses: rojopolis/spellcheck-github-actions@0.9.1
+      uses: rojopolis/spellcheck-github-actions@0.16.0

.spellcheck.yaml

@@ -9,8 +9,8 @@ matrix:
     encoding: utf-8
   pipeline:
     - pyspelling.filters.markdown:
-      markdown_extensions:
-      - markdown.extensions.extra:
+        markdown_extensions:
+        - pymdownx.extra:
     - pyspelling.filters.html:
         comments: true
         attributes: