Make snapshot release in goreleaser if from main (#1899)

## Description

This makes sure we switch between `--snapshot` and regular release based of we are doing it from main branch.

## Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No 

## Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [x] 💻 CI/Deployment
- [ ] 🐹 Trivial/Minor

## Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* fixes https://github.com/alcionai/corso/issues/1873

## Test Plan

<!-- How will this be tested prior to merging.-->
- [x] 💪 Manual
- [ ] ⚡ Unit test
- [ ] 💚 E2E

.github/workflows/ci.yml

@@ -398,11 +398,20 @@ jobs:
         with:
           go-version-file: src/go.mod
 
+      - name: Decide goreleaser release mode
+        shell: bash
+        run: |
+          if test '${{ github.ref }}' = "refs/heads/main"; then
+            echo "grflags=--snapshot" >> $GITHUB_ENV
+          else
+            echo "grflags=" >> $GITHUB_ENV
+          fi
+
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v4
         with:
           version: latest
-          args: release --rm-dist --timeout 500m
+          args: release --rm-dist --timeout 500m ${{ env.grflags }}
           workdir: src
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}