workflows: Fix security issues

read-all permissions gives access to e.g. security-events, which these
don't need, and can easily lead to leaks

Co-Authored-By: 13x1 <tori@disroot.org>
Co-Authored-By: basti564 <e3e@disroot.org>

.github/workflows/codeowners.yml

@@ -24,6 +24,9 @@ on:
   pull_request_target:
     types: [opened, ready_for_review, synchronize, reopened, edited]
 
+# We don't need any default GitHub token
+permissions: {}
+
 env:
   OWNERS_FILE: ci/OWNERS
   # Don't do anything on draft PRs

.github/workflows/editorconfig.yml

@@ -1,6 +1,8 @@
 name: "Checking EditorConfig"
 
-permissions: read-all
+permissions:
+  pull-requests: read
+  contents: read
 
 on:
   # avoids approving first time contributors

.github/workflows/manual-nixos.yml

@@ -1,6 +1,7 @@
 name: "Build NixOS manual"
 
-permissions: read-all
+permissions:
+  contents: read
 
 on:
   pull_request_target:

.github/workflows/manual-nixpkgs.yml

@@ -1,6 +1,7 @@
 name: "Build Nixpkgs manual"
 
-permissions: read-all
+permissions:
+  contents: read
 
 on:
   pull_request_target:

.github/workflows/nix-parse.yml

@@ -1,6 +1,8 @@
 name: "Check whether nix files are parseable"
 
-permissions: read-all
+permissions:
+  pull-requests: read
+  contents: read
 
 on:
   # avoids approving first time contributors