feat(codebuild): add new environment types (aws#32729)

### Issue # (if applicable)

Closes aws#32728.

### Reason for this change

Recently, CodeBuild released a new set of environment types which can be found [here](https://docs.aws.amazon.com/codebuild/latest/APIReference/API_CreateFleet.html#CodeBuild-CreateFleet-request-environmentType): `LINUX_EC2`, `ARM_EC2` and `WINDOWS_EC2`. The CDK needs to be extended to support these new environment types.

### Description of changes

Added `LINUX_EC2`, `ARM_EC2` and `WINDOWS_EC2` values to [EnvironmentType](https://github.com/aws/aws-cdk/blob/main/packages/aws-cdk-lib/aws-codebuild/lib/environment-type.ts).

### Description of how you validated changes

Tests has been added. I ensured that the CDK was able to build, and that the output CloudFormation stack had the correct resources.

### Checklist
- [X] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

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

packages/aws-cdk-lib/aws-codebuild/lib/environment-type.ts

@@ -16,4 +16,10 @@ export enum EnvironmentType {
   WINDOWS_SERVER_2022_CONTAINER = 'WINDOWS_SERVER_2022_CONTAINER',
   /** MacOS ARM container */
   MAC_ARM = 'MAC_ARM',
+  /** Linux EC2 */
+  LINUX_EC2 = 'LINUX_EC2',
+  /** ARM EC2 */
+  ARM_EC2 = 'ARM_EC2',
+  /** Windows EC2 */
+  WINDOWS_EC2 = 'WINDOWS_EC2',
 }

packages/aws-cdk-lib/aws-codebuild/test/fleet.test.ts

@@ -26,6 +26,78 @@ test('can construct a default fleet', () => {
   expect(fleet.environmentType).toEqual(codebuild.EnvironmentType.LINUX_CONTAINER);
 });
 
+test('can construct a LINUX_EC2 fleet', () => {
+  // GIVEN
+  const stack = new cdk.Stack();
+
+  // WHEN
+  const fleet = new codebuild.Fleet(stack, 'Fleet', {
+    computeType: codebuild.FleetComputeType.SMALL,
+    environmentType: codebuild.EnvironmentType.LINUX_EC2,
+    baseCapacity: 1,
+  });
+
+  // THEN
+  Template.fromStack(stack).hasResourceProperties('AWS::CodeBuild::Fleet', {
+    Name: Match.absent(),
+    BaseCapacity: 1,
+    ComputeType: 'BUILD_GENERAL1_SMALL',
+    EnvironmentType: 'LINUX_EC2',
+  });
+  expect(cdk.Token.isUnresolved(fleet.fleetName)).toBeTruthy();
+  expect(cdk.Token.isUnresolved(fleet.fleetArn)).toBeTruthy();
+  expect(fleet.computeType).toEqual(codebuild.FleetComputeType.SMALL);
+  expect(fleet.environmentType).toEqual(codebuild.EnvironmentType.LINUX_EC2);
+});
+
+test('can construct an ARM_EC2 fleet', () => {
+  // GIVEN
+  const stack = new cdk.Stack();
+
+  // WHEN
+  const fleet = new codebuild.Fleet(stack, 'Fleet', {
+    computeType: codebuild.FleetComputeType.SMALL,
+    environmentType: codebuild.EnvironmentType.ARM_EC2,
+    baseCapacity: 1,
+  });
+
+  // THEN
+  Template.fromStack(stack).hasResourceProperties('AWS::CodeBuild::Fleet', {
+    Name: Match.absent(),
+    BaseCapacity: 1,
+    ComputeType: 'BUILD_GENERAL1_SMALL',
+    EnvironmentType: 'ARM_EC2',
+  });
+  expect(cdk.Token.isUnresolved(fleet.fleetName)).toBeTruthy();
+  expect(cdk.Token.isUnresolved(fleet.fleetArn)).toBeTruthy();
+  expect(fleet.computeType).toEqual(codebuild.FleetComputeType.SMALL);
+  expect(fleet.environmentType).toEqual(codebuild.EnvironmentType.ARM_EC2);
+});
+
+test('can construct a WINDOWS_EC2 fleet', () => {
+  // GIVEN
+  const stack = new cdk.Stack();
+
+  // WHEN
+  const fleet = new codebuild.Fleet(stack, 'Fleet', {
+    computeType: codebuild.FleetComputeType.MEDIUM,
+    environmentType: codebuild.EnvironmentType.WINDOWS_EC2,
+    baseCapacity: 1,
+  });
+
+  // THEN
+  Template.fromStack(stack).hasResourceProperties('AWS::CodeBuild::Fleet', {
+    Name: Match.absent(),
+    BaseCapacity: 1,
+    ComputeType: 'BUILD_GENERAL1_MEDIUM',
+    EnvironmentType: 'WINDOWS_EC2',
+  });
+  expect(cdk.Token.isUnresolved(fleet.fleetName)).toBeTruthy();
+  expect(cdk.Token.isUnresolved(fleet.fleetArn)).toBeTruthy();
+  expect(fleet.computeType).toEqual(codebuild.FleetComputeType.MEDIUM);
+  expect(fleet.environmentType).toEqual(codebuild.EnvironmentType.WINDOWS_EC2);
+});
+
 test('can construct a fleet with a specified name', () => {
   // GIVEN
   const stack = new cdk.Stack();