chore(ci): set env var correctly on windows (#355)

* set env var correctly on windows

* split

* use bash

Author: mabaasit

.github/workflows/check-test.yaml

@@ -32,11 +32,13 @@ jobs:
       - name: Sets env vars
         if: github.event_name == 'pull_request'
         run: echo "SINCE_REF=remotes/origin/main" >> $GITHUB_ENV
+        shell: bash
 
       # On main we run all the checks with changes since the last commit
       - name: Sets env vars (main)
         if: github.event_name != 'pull_request'
         run: echo "SINCE_REF=HEAD~1" >> $GITHUB_ENV
+        shell: bash
 
       - name: Install Deps Ubuntu
         if: ${{ runner.os == 'Linux' }}