build(deps): update actions/setup-node requirement to v2.1.5

Updates the requirements on [actions/setup-node](https://github.com/actions/setup-node) to permit the latest version.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](https://github.com/actions/setup-node/commits/46071b5c7a2e0c34e49c3cb8a0e792e86e18d5ea)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/blog.yaml

@@ -62,7 +62,7 @@ jobs:
             ./content/blog
             ./static/blog
 
-      - uses: actions/setup-node@v1
+      - uses: actions/setup-node@v2.1.5
         with:
           node-version: "12"
       - uses: actions/cache@v2

.github/workflows/release_main.yml

@@ -18,7 +18,7 @@ jobs:
     steps:
       - name: Check out code
         uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/setup-node@v2.1.5
         with:
           node-version: "14"
       - name: Extract version
@@ -43,7 +43,7 @@ jobs:
     steps:
       - name: Check out code
         uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/setup-node@v2.1.5
         with:
           node-version: "14"
       - name: Cache Node.js modules