chore: bump step-security/harden-runner to v2.19.0

Pin to 8d3c67de8e2fe68ef647c8db1e6a09f647780f40 (v2.19.0), latest
release. Part of an org-wide harden-runner audit to bring workflows
up to the ≥v2.17.0 policy bar.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antitree

.github/workflows/actionlint.yaml

@@ -24,7 +24,7 @@ jobs:
     name: Action lint
     runs-on: ubuntu-latest
     steps:
-      - uses: step-security/harden-runner@fe104658747b27e96e4f7e80cd0a94068e53901d # v2.16.1
+      - uses: step-security/harden-runner@8d3c67de8e2fe68ef647c8db1e6a09f647780f40 # v2.19.0
         with:
           egress-policy: block
           allowed-endpoints: >

.github/workflows/zizmor.yaml

@@ -20,7 +20,7 @@ jobs:
       contents: read # Clone the repository
       security-events: write # Upload SARIF results to Code Scanning
     steps:
-      - uses: step-security/harden-runner@fe104658747b27e96e4f7e80cd0a94068e53901d # v2.16.1
+      - uses: step-security/harden-runner@8d3c67de8e2fe68ef647c8db1e6a09f647780f40 # v2.19.0
         with:
           egress-policy: block
           allowed-endpoints: >