ci: move external_deps job from cirrus-ci back to github actions

This partially reverts commit 7d0479c558.

The job has been particularly unstable when used with docker on
cirrus-ci, which is especially bad as it's meant to be a non-flaky and
simple test.

.cirrus.yml

@@ -25,13 +25,3 @@ freebsd_task:
     - sudo -u cirrus gmake unittest
   oldtest_script:
     - sudo -u cirrus gmake oldtest
-
-external_deps_task:
-  container:
-    dockerfile: ci/Dockerfile.external_deps
-  deps_script:
-    - cmake -S cmake.deps --preset external_deps
-    - cmake --build .deps
-  build_script:
-    - cmake --preset ci
-    - cmake --build build

.github/workflows/test.yml

@@ -301,3 +301,41 @@ jobs:
         run: |
           cd test/old/testdir
           mingw32-make VERBOSE=1
+
+  with-external-deps:
+    runs-on: ubuntu-22.04
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Install dependencies
+        run: |
+          sudo add-apt-repository ppa:neovim-ppa/stable
+          ./.github/scripts/install_deps.sh
+          sudo apt-get install -y \
+            libluajit-5.1-dev \
+            libmsgpack-dev \
+            libtermkey-dev \
+            libunibilium-dev \
+            libuv1-dev \
+            lua-filesystem \
+            lua-lpeg \
+            luajit \
+            lua-luv-dev
+            # libtree-sitter-dev \
+            # libvterm-dev
+
+            # Remove comments from packages once we start using these external
+            # dependencies.
+
+      - uses: ./.github/actions/cache
+
+      - name: Build third-party deps
+        run: |
+          cmake -S cmake.deps --preset external_deps
+          cmake --build .deps
+
+      - name: Build
+        run: |
+          cmake --preset ci
+          cmake --build build

ci/Dockerfile.external_deps

@@ -1,22 +0,0 @@
-FROM ubuntu:22.04
-
-RUN apt-get update && \
-    apt-get install -y software-properties-common && \
-    add-apt-repository ppa:neovim-ppa/stable && \
-    apt-get install -y ninja-build \
-            gettext \
-            cmake \
-            unzip \
-            curl \
-            git \
-            libluajit-5.1-dev \
-            libmsgpack-dev \
-            libtermkey-dev \
-            libunibilium-dev \
-            libuv1-dev \
-            lua-filesystem \
-            lua-lpeg \
-            luajit \
-            lua-luv-dev \
-            libtree-sitter-dev \
-            libvterm-dev