Migrate to Node 20 on CI via GitHub Actions major upgrades (#372)

* Update first party actions to Node 20 majors.

* Update Gradle cache actions to Node 20 majors.

README.md

@@ -49,7 +49,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Enable KVM
         run: |
@@ -76,7 +76,7 @@ jobs:
         target: [default, google_apis]
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Enable KVM
         run: |
@@ -102,7 +102,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Enable KVM
         run: |
@@ -121,8 +121,8 @@ jobs:
 
 We can significantly reduce emulator startup time by setting up AVD snapshot caching:
 
-1. add a `gradle/gradle-build-action@v2` step for caching Gradle, more details see [#229](https://github.com/ReactiveCircus/android-emulator-runner/issues/229)
-2. add an `actions/cache@v3` step for caching the `avd`
+1. add a `gradle/actions/setup-gradle@v3` step for caching Gradle, more details see [#229](https://github.com/ReactiveCircus/android-emulator-runner/issues/229)
+2. add an `actions/cache@v4` step for caching the `avd`
 3. add a `reactivecircus/android-emulator-runner@v2` step to generate a clean snapshot - specify `emulator-options` without `no-snapshot`
 4. add another `reactivecircus/android-emulator-runner@v2` step to run your tests using existing AVD / snapshot - specify `emulator-options` with `no-snapshot-save`
 
@@ -135,7 +135,7 @@ jobs:
         api-level: [21, 23, 29]
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Enable KVM
         run: |
@@ -144,10 +144,10 @@ jobs:
           sudo udevadm trigger --name-match=kvm
 
       - name: Gradle cache
-        uses: gradle/gradle-build-action@v2
+        uses: gradle/actions/setup-gradle@v3
         
       - name: AVD cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         id: avd-cache
         with:
           path: |