chore: continue-on-error for nightly (#356)

## 📃 Summary

will investigate later why nightly hangs

.github/workflows/main.yml

@@ -54,7 +54,7 @@ jobs:
     timeout-minutes: 1
     strategy:
       matrix:
-        neovim_version: ['v0.7.2', 'v0.8.3', 'v0.9.5', 'v0.10.0', 'nightly']
+        neovim_version: ['v0.7.2', 'v0.8.3', 'v0.9.5', 'v0.10.0']
 
     steps:
       - uses: actions/checkout@v4
@@ -93,6 +93,51 @@ jobs:
       - name: run tests
         run: make test-ci
 
+  tests-nightly:
+    needs:
+      - lint
+      - documentation
+    runs-on: ubuntu-latest
+    timeout-minutes: 1
+    continue-on-error: true
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - run: date +%F > todays-date
+
+      - name: restore cache for today's nightly.
+        uses: actions/cache@v4
+        with:
+          path: _neovim
+          key: ${{ runner.os }}-x64-${{ hashFiles('todays-date') }}
+
+      - name: restore luals cache
+        uses: actions/cache@v4
+        id: cache
+        with:
+          path: .ci/lua-ls
+          key: ${{ env.LUA_LS_VERSION }}
+
+      - name: setup luals
+        if: ${{ steps.cache.outputs.cache-hit != 'true' }}
+        run: mkdir -p .ci/lua-ls && curl -sL "https://github.com/LuaLS/lua-language-server/releases/download/${{ env.LUA_LS_VERSION }}/lua-language-server-${{ env.LUA_LS_VERSION }}-linux-x64.tar.gz" | tar xzf - -C "${PWD}/.ci/lua-ls"
+
+      - name: setup neovim
+        uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+
+      - name: run luals
+        run: |
+          export PATH="${PWD}/.ci/lua-ls/bin:${PATH}"
+          nvim --version
+          make luals-ci
+
+      - name: run tests
+        run: make test-ci
+
   release:
     name: release
     if: ${{ github.ref == 'refs/heads/main' }}