Update test_upb.yml to use ubuntu-22

Merge pull request #21694 from protocolbuffers/esrauchg-patch-1
Update test_upb.yml to use ubuntu-22

Author: esrauchg

.github/workflows/test_upb.yml

@@ -19,7 +19,7 @@ jobs:
         config:
           - { name: "Fastbuild" }
           - { name: "Optimized", flags: "-c opt" }
-          - { name: "ASAN", flags: "--config=asan -c dbg", exclude-targets: "-//benchmarks:benchmark -//python/...", runner: ubuntu-20-4core }
+          - { name: "ASAN", flags: "--config=asan -c dbg", exclude-targets: "-//benchmarks:benchmark -//python/...", runner: ubuntu-22-4core }
           - { name: "UBSAN", flags: "--config=ubsan -c dbg", exclude-targets: "-//benchmarks:benchmark -//python/... -//lua/..." }
           - { name: "32-bit", flags: "--copt=-m32 --linkopt=-m32", exclude-targets: "-//benchmarks:benchmark -//python/..." }
           # TODO: b/297027295 - Add 32-bit ASAN test