Update the sample in README.md with explicit permission control. (#31)

* Update the sample in README.md with explicit permission control.

By adding the explict permission declaration, user can deploy the
HTML document with default workflow permission of their repository.

    permissions:
      contents: write
      pages: write

* Removed unneccesary permissions:pages: control.

README.md

@@ -17,6 +17,8 @@ on:
 jobs:
   deploy:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       - uses: DenverCoder1/[email protected]
         with:
@@ -48,6 +50,8 @@ on:
 jobs:
   deploy:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       - uses: DenverCoder1/[email protected]
         with: