fix(acm): update CertificateRequestorFunction runtime

Fixes aws#4610

Author: jakerullman

packages/@aws-cdk/aws-certificatemanager/lambda-packages/dns_validated_certificate_handler/.node-version

@@ -1 +1 @@
-8.10.0
+10.3.0

packages/@aws-cdk/aws-certificatemanager/lib/dns-validated-certificate.ts

@@ -61,7 +61,7 @@ export class DnsValidatedCertificate extends cdk.Resource implements ICertificat
         const requestorFunction = new lambda.Function(this, 'CertificateRequestorFunction', {
             code: lambda.Code.fromAsset(path.resolve(__dirname, '..', 'lambda-packages', 'dns_validated_certificate_handler', 'lib')),
             handler: 'index.certificateRequestHandler',
-            runtime: lambda.Runtime.NODEJS_8_10,
+            runtime: lambda.Runtime.NODEJS_10_X,
             timeout: cdk.Duration.minutes(15),
             role: props.customResourceRole
         });

packages/@aws-cdk/aws-certificatemanager/test/test.dns-validated-certificate.ts

@@ -32,7 +32,7 @@ export = {
     }));
     expect(stack).to(haveResource('AWS::Lambda::Function', {
       Handler: 'index.certificateRequestHandler',
-      Runtime: 'nodejs8.10',
+      Runtime: 'nodejs10.x',
       Timeout: 900,
     }));
     expect(stack).to(haveResource('AWS::IAM::Policy', {