feat: enable stack tagging

[EHitchc]

Fixes #730

The StackDeployment type accessed on the jobForDeploy method already has a tags property with the desired Key/Value pairs. This added code snippet converts the record of Key/Value pairs into the JSON-formatted string required by the inputs for the underlying aws-cloudformation-github-deploy action (https://github.com/aws-actions/aws-cloudformation-github-deploy/blob/1802e08d2ea549569d23bf4a7d704b5242cfc878/action.yml#L49-L51) before generating the final yaml file.

Sample workflow generated by added test (note addition of tags to deploy step):

      name: deploy
      on:
        push:
          branches:
            - main
        workflow_dispatch: {}
      jobs:
        Build-Build:
          name: Synthesize
          permissions:
            contents: read
            id-token: none
          runs-on: ubuntu-latest
          needs: []
          env: {}
          steps:
            - name: Checkout
              uses: actions/checkout@v6
            - name: Install
              run: yarn
            - name: Build
              run: yarn build
            - name: Upload cdk.out
              uses: actions/upload-artifact@v7
              with:
                name: cdk.out
                path: cdk.out
                include-hidden-files: true
        Assets-FileAsset1:
          name: Publish Assets Assets-FileAsset1
          needs:
            - Build-Build
          permissions:
            contents: read
            id-token: none
          runs-on: ubuntu-latest
          outputs:
            asset-hash: ${{ steps.Publish.outputs.asset-hash }}
          steps:
            - name: Download cdk.out
              uses: actions/download-artifact@v8
              with:
                name: cdk.out
                path: github.out
            - name: Install
              run: npm install --no-save cdk-assets
            - name: Authenticate Via GitHub Secrets
              uses: aws-actions/configure-aws-credentials@v6
              with:
                aws-region: us-west-2
                role-duration-seconds: 1800
                role-skip-session-tagging: true
                aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
                aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
            - id: Publish
              name: Publish Assets-FileAsset1
              run: /bin/bash ./cdk.out/assembly-MyStack/publish-Assets-FileAsset1-step.sh
        MyStack-MyStack-Deploy:
          name: Deploy MyStack098574E7
          permissions:
            contents: read
            id-token: none
          needs:
            - Build-Build
            - Assets-FileAsset1
          runs-on: ubuntu-latest
          steps:
            - name: Authenticate Via GitHub Secrets
              uses: aws-actions/configure-aws-credentials@v6
              with:
                aws-region: us-east-1
                role-duration-seconds: 1800
                role-skip-session-tagging: true
                aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
                aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
                role-to-assume: arn:aws:iam::111111111111:role/cdk-hnb659fds-deploy-role-111111111111-us-east-1
                role-external-id: Pipeline
            - id: Deploy
              uses: aws-actions/aws-cloudformation-github-deploy@v2
              with:
                name: MyStack-MyStack
                template: https://cdk-hnb659fds-assets-111111111111-us-east-1.s3.us-east-1.amazonaws.com/${{
                  needs.Assets-FileAsset1.outputs.asset-hash }}.json
                fail-on-empty-changeset: false
                role-arn: arn:aws:iam::111111111111:role/cdk-hnb659fds-cfn-exec-role-111111111111-us-east-1
                tags: '[{"Key":"Environment","Value":"Production"},{"Key":"Project","Value":"MyProject"}]'