fix(ci): pin reusable-workflow @main refs to SHA

Pins projectbluefin/actions @main refs to 7f79969 # v1 in execute-release.yml, pr-release-gate.yml, promote-testing-to-main.yml, release-reminder.yml. Eliminates non-deterministic CI from floating @main refs. Renovate keeps SHAs current via C3 grouping rule.

Author: castrojo

.github/workflows/execute-release.yml

@@ -20,7 +20,7 @@ jobs:
       issues: write
       packages: write
       pull-requests: write
-    uses: projectbluefin/actions/.github/workflows/reusable-execute-release.yml@main
+    uses: projectbluefin/actions/.github/workflows/reusable-execute-release.yml@7f79969c2ff74c51ac7f385cb0a86414975308d7 # v1
     with:
       registry: ghcr.io/projectbluefin
       variants: >-
@@ -38,7 +38,7 @@ jobs:
       contents: write
       id-token: write
       packages: read
-    uses: projectbluefin/actions/.github/workflows/reusable-release.yml@main
+    uses: projectbluefin/actions/.github/workflows/reusable-release.yml@7f79969c2ff74c51ac7f385cb0a86414975308d7 # v1
     with:
       stream_name: stable
       image: ghcr.io/projectbluefin/dakota

.github/workflows/pr-release-gate.yml

@@ -16,7 +16,7 @@ jobs:
       issues: write
       packages: read
       pull-requests: write
-    uses: projectbluefin/actions/.github/workflows/reusable-release-gate.yml@main
+    uses: projectbluefin/actions/.github/workflows/reusable-release-gate.yml@7f79969c2ff74c51ac7f385cb0a86414975308d7 # v1
     with:
       repo: ${{ github.repository }}
       registry: ghcr.io/projectbluefin

.github/workflows/promote-testing-to-main.yml

@@ -169,7 +169,7 @@ jobs:
       issues: write
       packages: read
       pull-requests: write
-    uses: projectbluefin/actions/.github/workflows/reusable-release-gate.yml@main
+    uses: projectbluefin/actions/.github/workflows/reusable-release-gate.yml@7f79969c2ff74c51ac7f385cb0a86414975308d7 # v1
     with:
       repo: ${{ github.repository }}
       pr_number: ${{ needs.promote.outputs.pr_number }}

.github/workflows/release-reminder.yml

@@ -13,7 +13,7 @@ jobs:
       contents: read
       issues: write
       pull-requests: write
-    uses: projectbluefin/actions/.github/workflows/reusable-release-reminder.yml@main
+    uses: projectbluefin/actions/.github/workflows/reusable-release-reminder.yml@7f79969c2ff74c51ac7f385cb0a86414975308d7 # v1
     with:
       days_warn: 7
       days_escalate: 14