Run CI on every push to develop branch instead of on a schedule

Also remove logic to skip CI if it already ran for the same commit

This prevents the CI badge in the README from showing a failure due to a skipped CI run and
results in more up-to-date ccache caches for each PR's initial CI run

.github/workflows/github.yml

@@ -6,9 +6,8 @@ on:
       - features/*
       - beta
       - master
+      - develop
   pull_request:
-  schedule:
-    - cron: '0 2 * * *'
   workflow_dispatch:
 
 env:
@@ -16,59 +15,7 @@ env:
   BUILD_TYPE: Release
 
 jobs:
-  check_last_build:
-    if: github.event.schedule != ''
-    runs-on: ubuntu-latest
-    outputs:
-      skip_build: ${{ steps.check_if_built.outputs.skip_build }}
-    defaults:
-      run:
-        shell: bash
-    steps:
-      - name: Get repo name
-        id: get_repo_name
-        run: echo "::set-output name=value::${GITHUB_REPOSITORY#*/}"
-
-      - name: Get last successful build for ${{ github.sha }}
-        uses: octokit/request-action@v2.1.9
-        id: get_last_scheduled_run
-        with:
-          route: GET /repos/{owner}/{repo}/actions/runs
-          owner: ${{ github.repository_owner }}
-          repo: ${{ steps.get_repo_name.outputs.value }}
-          status: success
-          per_page: 1
-          head_sha: ${{ github.sha }}
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Check if successful build of the current commit exists
-        id: check_if_built
-        run: |
-          if [ ${{ fromJson(steps.get_last_scheduled_run.outputs.data).total_count }} -gt 0 ]; then
-            echo '::set-output name=skip_build::1'
-          else
-            echo '::set-output name=skip_build::0'
-          fi
-
-      - name: Cancel current run
-        if: steps.check_if_built.outputs.skip_build == 1
-        uses: octokit/request-action@v2.1.9
-        with:
-          route: POST /repos/{owner}/{repo}/actions/runs/{run_id}/cancel
-          owner: ${{ github.repository_owner }}
-          repo: ${{ steps.get_repo_name.outputs.value }}
-          run_id: ${{ github.run_id }}
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Wait for the run to be cancelled
-        if: steps.check_if_built.outputs.skip_build == 1
-        run: sleep 60
-
   build:
-    needs: check_last_build
-    if: always() && needs.check_last_build.skip_build != 1
     strategy:
       matrix:
         include:
@@ -199,9 +146,9 @@ jobs:
         max-size: "5G"
         verbose: 2
 
-    - name: Ccache for everything but PRs
+    - name: Ccache for vcmi/vcmi's develop branch
       uses: hendrikmuhs/ccache-action@v1.2
-      if: ${{ github.event.number == '' }}
+      if: ${{ github.event.number == '' && github.ref == 'refs/heads/develop' }}
       with:
         key: ${{ matrix.preset }}-no-PR
         restore-keys: |