feat(codebuild): allow setting concurrent build limit (aws#14185)

Add support for specifying the concurrent build limit for codebuild project.

This is identical to aws#14099 - which could not be merged because it was based on fork in corporate github organization.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-codebuild/README.md

@@ -648,3 +648,17 @@ new codebuild.Project(stack, 'MyProject', {
   queuedTimeout: Duration.minutes(30)
 });
 ```
+
+## Limiting concurrency
+
+By default if a new build is triggered it will be run even if there is a previous build already in progress.
+It is possible to limit the maximum concurrent builds to value between 1 and the account specific maximum limit.
+By default there is no explicit limit.
+
+```ts
+import * as codebuild from '@aws-cdk/aws-codebuild';
+
+new codebuild.Project(stack, 'MyProject', {
+  concurrentBuildLimit: 1
+});
+```

packages/@aws-cdk/aws-codebuild/lib/project.ts

@@ -584,6 +584,13 @@ export interface CommonProjectProps {
    * @default - no queue timeout is set
    */
   readonly queuedTimeout?: Duration
+
+  /**
+   * Maximum number of concurrent builds. Minimum value is 1 and maximum is account build limit.
+   *
+   * @default - no explicit limit is set
+   */
+  readonly concurrentBuildLimit?: number
 }
 
 export interface ProjectProps extends CommonProjectProps {
@@ -917,6 +924,7 @@ export class Project extends ProjectBase {
       name: this.physicalName,
       timeoutInMinutes: props.timeout && props.timeout.toMinutes(),
       queuedTimeoutInMinutes: props.queuedTimeout && props.queuedTimeout.toMinutes(),
+      concurrentBuildLimit: props.concurrentBuildLimit,
       secondarySources: Lazy.any({ produce: () => this.renderSecondarySources() }),
       secondarySourceVersions: Lazy.any({ produce: () => this.renderSecondarySourceVersions() }),
       secondaryArtifacts: Lazy.any({ produce: () => this.renderSecondaryArtifacts() }),

packages/@aws-cdk/aws-codebuild/test/test.project.ts

@@ -1409,6 +1409,29 @@ export = {
     },
   },
 
+  'Maximum concurrency': {
+    'can limit maximum concurrency'(test: Test) {
+      // GIVEN
+      const stack = new cdk.Stack();
+
+      // WHEN
+      new codebuild.Project(stack, 'Project', {
+        source: codebuild.Source.s3({
+          bucket: new s3.Bucket(stack, 'Bucket'),
+          path: 'path',
+        }),
+        concurrentBuildLimit: 1,
+      });
+
+      // THEN
+      expect(stack).to(haveResourceLike('AWS::CodeBuild::Project', {
+        ConcurrentBuildLimit: 1,
+      }));
+
+      test.done();
+    },
+  },
+
   'can be imported': {
     'by ARN'(test: Test) {
       const stack = new cdk.Stack();