Minimal token permissions

See https://github.com/tokio-rs/tokio/pull/5072

.github/workflows/check.yml

@@ -1,3 +1,5 @@
+permissions:
+  contents: read
 on:
   push:
     branches: [main]
@@ -20,6 +22,9 @@ jobs:
   clippy:
     runs-on: ubuntu-latest
     name: ${{ matrix.toolchain }} / clippy
+    permissions:
+      contents: read
+      checks: write
     strategy:
       fail-fast: false
       matrix:

.github/workflows/nostd.yml

@@ -1,3 +1,5 @@
+permissions:
+  contents: read
 on:
   push:
     branches: [main]

.github/workflows/safety.yml

@@ -1,3 +1,5 @@
+permissions:
+  contents: read
 on:
   push:
     branches: [main]

.github/workflows/scheduled.yml

@@ -1,3 +1,5 @@
+permissions:
+  contents: read
 on:
   push:
     branches: [main]

.github/workflows/test.yml

@@ -1,3 +1,5 @@
+permissions:
+  contents: read
 on:
   push:
     branches: [main]