Get rid of duplicate code

.github/actions/prepare_ubuntu_runner/action.yaml

@@ -0,0 +1,23 @@
+name: "Prepare Ubuntu runner"
+description: "Prepare Ubuntu runner"
+runs:
+  using: "composite"
+  steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: "3.1.1" # TODO: keep this somewhere where it's easy to change
+
+    - name: Install gems
+      shell: bash
+      run: bundle install
+
+    - name: Install FVM
+      shell: bash
+      run: curl -fsSL https://fvm.app/install.sh | bash
+
+    - name: Set up FVM
+      shell: bash
+      run: fvm use

.github/workflows/release-workflow.yaml

@@ -10,21 +10,8 @@ jobs:
     name: Run tests
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-
-      - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: "3.1.1" # TODO: keep this somewhere where it's easy to change
-
-      - name: Install gems
-        run: bundle install
-
-      - name: Install FVM
-        run: curl -fsSL https://fvm.app/install.sh | bash
-
-      - name: Set up FVM
-        run: fvm use
+      - uses: ./.github/actions/prepare_ubuntu_runner
+        id: prepare_ubuntu_runner
 
       - name: Run virtual machine tests
         run: bundle exec fastlane run_vm_tests