- Kubernetes is now built with Go `1.21.0`. ([#118996](https://github.com/kubernetes/kubernetes/pull/118996), [@cpanato](https://github.com/cpanato))
- Kubernetes is now built with Go `1.21.1`. ([#120493](https://github.com/kubernetes/kubernetes/pull/120493), [@cpanato](https://github.com/cpanato))

## Changelog since v1.19.2

## Changes by Kind

### Feature

- Kubernetes is now built using go1.15.2
  - build: Update to k/repo-infra@v0.1.1 (supports go1.15.2)
  - build: Use go-runner:buster-v2.0.1 (built using go1.15.1)
  - bazel: Replace --features with Starlark build settings flag
  - hack/lib/util.sh: some bash cleanups
    
    - switched one spot to use kube::logging

        runner.onBuild((number, settingsBuilder) -> {
            settingsBuilder.put("http.cors.enabled", true);
            settingsBuilder.put("discovery.type", "single-node");
        }).build(newConfigs().clusterName(clusterName).numOfNode(1));

        // wait for yellow status
        runner.ensureYellow();

            String pomXml = PomBuilder.create()
                    .groupId("test")
                    .artifactId("test")
                    .version("1.0.0")
                    .build();

            Path pomFile = projectDir.resolve("pom.xml");
            Files.writeString(pomFile, pomXml);

            UpgradeContext context = createMockContext(projectDir);

        Metadata source = new Metadata(org.apache.maven.api.metadata.Metadata.newBuilder(
                        createMetadataFromArtifact(artifact).getDelegate(), true)
                .modelEncoding("UTF-16")
                .build());
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        new MetadataStaxWriter().write(baos, source.getDelegate());
        Metadata source2 =

/**
 * A semi-persistent mapping from keys to values. Values are automatically loaded by the cache, and
 * are stored in the cache until either evicted or manually invalidated. The common way to build
 * instances is using {@link CacheBuilder}.
 *
 * <p>Implementations of this interface are expected to be thread-safe, and can be safely accessed
 * by multiple concurrent threads.
 *

 *   public Graph load(Key key) throws AnyException {
 *     return createExpensiveGraph(key);
 *   }
 * };
 * LoadingCache<Key, Graph> cache = CacheBuilder.newBuilder().build(loader);
 * }
 *
 * <p>Since this example doesn't support reloading or bulk loading, it can also be specified much
 * more simply:
 *
 * {@snippet :

 * the fact that the problem reporter has/should not have information about the calling context and hence cannot provide
 * an expressive source hint for the model problem. Instead, the source hint is configured by the model builder before
 * it delegates to other components that potentially encounter problems. Then, the problem reporter can focus on
 * providing a simple error message, leaving the donkey work of creating a nice model problem to this component.

      return ImmutableMap.of();
    }
  }

  private static final ImmutableMap<Class<? extends Throwable>, Predicate<Throwable>> INSTANCE_OF =
      ImmutableMap.<Class<? extends Throwable>, Predicate<Throwable>>builder()
          .put(ArithmeticException.class, e -> e instanceof ArithmeticException)
          .put(
              ArrayIndexOutOfBoundsException.class,
              e -> e instanceof ArrayIndexOutOfBoundsException)

      return ImmutableMap.of();
    }
  }

  private static final ImmutableMap<Class<? extends Throwable>, Predicate<Throwable>> INSTANCE_OF =
      ImmutableMap.<Class<? extends Throwable>, Predicate<Throwable>>builder()
          .put(ArithmeticException.class, e -> e instanceof ArithmeticException)
          .put(
              ArrayIndexOutOfBoundsException.class,
              e -> e instanceof ArrayIndexOutOfBoundsException)