GitHub actions: add permission to read only

Author: wkliao

.github/workflows/openmpi.yml

@@ -1,4 +1,8 @@
 name: Using OpenMPI
+
+permissions:
+  contents: read
+
 on:
   push:
     branches:

.github/workflows/pnetcdf_c_master.yml

@@ -1,4 +1,8 @@
 name: Test PnetCDF-C master branch
+
+permissions:
+  contents: read
+
 on:
   workflow_dispatch:
     inputs:

.github/workflows/pnetcdf_c_official.yml

@@ -1,4 +1,8 @@
 name: Test PnetCDF-C latest official release
+
+permissions:
+  contents: read
+
 on:
   push:
     branches:

.github/workflows/static.yml

@@ -1,6 +1,9 @@
 # Simple workflow for deploying static content to GitHub Pages
 name: Deploy static content to Pages
 
+permissions:
+  contents: read
+
 on:
   # Runs on pushes targeting the default branch
   push: