Create Sha256sum file for each release binary (#14050)

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Create Sha256sum file for each release binary
A test release could be found here:
https://github.com/nushell/nightly/releases/tag/0.98.2

.github/workflows/release.yml

@@ -14,7 +14,7 @@ defaults:
     shell: bash
 
 jobs:
-  standard:
+  release:
     name: Nu
 
     strategy:
@@ -107,3 +107,26 @@ jobs:
         files: ${{ steps.nu.outputs.archive }}
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  sha256sum:
+    needs: release
+    name: Create Sha256sum
+    runs-on: ubuntu-latest
+    steps:
+    - name: Download Release Archives
+      env:
+        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      run: >-
+        gh release download ${{ github.ref_name }}
+        --repo ${{ github.repository }}
+        --pattern '*'
+        --dir release
+    - name: Create Checksums
+      run: cd release && shasum -a 256 * > ../SHA256SUMS
+    - name: Publish Checksums
+      uses: softprops/action-gh-release@v2.0.8
+      with:
+        draft: true
+        files: SHA256SUMS
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}