AWS CDK CodePipeLines with private NPM repo

pipeline.ts

const GHSecret = Secret.fromSecretNameV2(scope, 'GHSecret', 'github/read_registry');
const codeStarArn = '';

const input = CodePipelineSource.connection(props.repositoryName, props.repositoryBranch, {
  connectionArn: codeStarArn
});

return new CodePipeline(scope, `Pipeline`, {
  synthCodeBuildDefaults: {
    buildEnvironment: {
      environmentVariables: {
        GITHUB_ACCESS_TOKEN: {
          value: `${GHSecret.secretName}:GITHUB_ACCESS_TOKEN`,
          type: BuildEnvironmentVariableType.SECRETS_MANAGER,
        },
      },
    },
  },
  codeBuildDefaults: {
    buildEnvironment: {
      environmentVariables: {
        GITHUB_ACCESS_TOKEN: {
          value: `${GHSecret.secretName}:GITHUB_ACCESS_TOKEN`,
          type: BuildEnvironmentVariableType.SECRETS_MANAGER,
        },
      },
    },
  },
  synth: new ShellStep('Synth', {
    input,
    commands: [
      'mv -f .npmrc_ci .npmrc 2>/dev/null; true',
      'npm ci',
      'npm run build',
      'npx cdk synth',
    ],
  }),
});