adds some mkdocs (#198)

* adds some mkdocs

* more edits

mkdocs.yaml

@@ -0,0 +1,33 @@
+site_name: supabase-github-action
+site_url: https://supabase.github.io/supabase-github-action
+site_description: A GitHub action for interacting with your Supabase projects using the CLI. 
+
+repo_name: supabase/supabase-github-action
+repo_url: https://github.com/supabase/supabase-github-action
+
+nav:
+    - Welcome: 'index.md'
+
+theme:
+    name: 'material'
+    features:
+      - navigation.expand
+    favicon: 'assets/favicon.ico'
+    logo: 'assets/favicon.ico'
+    homepage: https://supabase.github.io/supabase-github-action
+    palette:
+        primary: black
+        accent: light green
+
+markdown_extensions:
+    - pymdownx.highlight:
+        linenums: true
+        guess_lang: false
+        use_pygments: true
+        pygments_style: default
+    - pymdownx.superfences
+    - pymdownx.tabbed:
+        alternate_style: true
+    - pymdownx.snippets
+    - pymdownx.tasklist
+    - admonition