Use ubuntu-18.04 container in rust tests

.github/workflows/flaky.yml

@@ -6,10 +6,20 @@ on:
 
 jobs:
   flaky:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
+    container:
+      image: ubuntu:18.04
 
     steps:
     - uses: actions/checkout@v3
+    - name: Install needed dependencies
+      run: |
+        apt-get update && apt-get install -y curl
+        apt-get install build-essential -y
+    - uses: actions-rs/toolchain@v1
+      with:
+        toolchain: stable
+        override: true
     - name: Install cargo-flaky
       run: cargo install cargo-flaky
     - name: Run cargo flaky 100 times