Add permissions to GitHub Action workflows (#192)

Author: jaywonchung

.github/workflows/check_homepage_build.yaml

@@ -1,4 +1,6 @@
 name: Check homepage build
+permissions:
+  contents: read
 
 on:
   pull_request:

.github/workflows/deploy_homepage.yaml

@@ -1,4 +1,7 @@
 name: Deploy homepage
+permissions:
+  contents: write
+
 on:
   push:
     branches:

.github/workflows/publish_crates_io.yaml

@@ -1,4 +1,6 @@
 name: Release
+permissions:
+  contents: read
 
 on:
   push:

.github/workflows/push_docker.yaml

@@ -1,4 +1,7 @@
 name: Push Docker image
+permissions:
+  contents: read
+  actions: write
 
 on:
   push:

.github/workflows/zeus_fmt_lint_test.yaml

@@ -1,4 +1,6 @@
 name: (Zeus) Check format, lint, and test
+permissions:
+  contents: read
 
 on:
   pull_request:

.github/workflows/zeusd_fmt_lint_test.yaml

@@ -1,4 +1,6 @@
 name: (Zeusd) Check format, lint, and test
+permissions:
+  contents: read
 
 on:
   pull_request: