CI: Restrict default permissions

Reduces risk of arbitrary code is run by attacker.

Author: tacaswell

.github/workflows/release.yml

@@ -1,6 +1,8 @@
 ---
 
 name: Release
+permissions:
+  contents: read
 on:
   release:
     types:

.github/workflows/reviewdog.yml

@@ -1,5 +1,7 @@
 ---
 name: Linting
+permissions:
+  contents: read
 on:
   push:
     branches-ignore:

.github/workflows/tests.yml

@@ -1,6 +1,8 @@
 ---
 
 name: Tests
+permissions:
+  contents: read
 
 on:
   push: