Pin actions to a full length commit SHA

- Pinned actions by SHA https://github.com/ossf/scorecard/blob/main/docs/checks.md#pinned-dependencies
- Included permissions for the action. https://github.com/ossf/scorecard/blob/main/docs/checks.md#token-permissions

>Pin actions to a full length commit SHA

>Pinning an action to a full length commit SHA is currently the only way to use an action as an immutable release. Pinning to a particular SHA helps mitigate the risk of a bad actor adding a backdoor to the action's repository, as they would need to generate a SHA-1 collision for a valid Git object payload.

https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-third-party-actions

.github/workflows/go.yml

@@ -10,6 +10,9 @@ concurrency:
   group: ${{ github.head_ref }}/go
   cancel-in-progress: true
 
+permissions:
+  contents: read
+
 jobs:
 
   build:
@@ -18,13 +21,13 @@ jobs:
     steps:
 
     - name: Set up Go 1.x
-      uses: actions/setup-go@v2
+      uses: actions/setup-go@bfdd3570ce990073878bf10f6b2d79082de49492 # v2
       with:
         go-version: ^1.13
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v2
+      uses: actions/checkout@629c2de402a417ea7690ca6ce3f33229e27606a5 # v2
 
     - name: Get dependencies
       run: |