update precommit markdownlint and add permissions on workflow files (#1246)

test out some precommit hooks and other updates

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

.github/workflows/arm_mac_gcc.yml

@@ -4,6 +4,9 @@ on:
     branches:
       - main
 
+permissions:
+  contents: read
+  
 jobs:
   arm64_gcc:
     name: ARM64 GCC

.github/workflows/pr_merged.yml

@@ -3,6 +3,10 @@ on:
   pull_request_target:
     types: [closed]
 
+permissions:
+  contents: write
+  pull-request: write
+  
 jobs:
   label-merged:
     name: Changelog needed