add istioctl-zsh-completion package (#53339)

- add istioctl-zsh-completion package
- add bash-completion dependency for istioctl-bash-completion

---------

Signed-off-by: Scott Schubert <[email protected]>

Author: sschubertchainguard

istio-1.26.yaml

@@ -1,7 +1,7 @@
 package:
   name: istio-1.26
   version: "1.26.0"
-  epoch: 1
+  epoch: 2
   description: Istio is an open source service mesh that layers transparently onto existing distributed applications.
   copyright:
     - license: Apache-2.0
@@ -71,6 +71,7 @@ subpackages:
         - istioctl-bash-completion=${{package.full-version}}
       runtime:
         - istioctl-${{vars.major-minor-version}}
+        - bash-completion
     pipeline:
       - runs: |
           mkdir -p "${{targets.contextdir}}"/usr/share/bash-completion/completions
@@ -79,6 +80,20 @@ subpackages:
       pipeline:
         - runs: stat /usr/share/bash-completion/completions/istioctl-${{vars.major-minor-version}}
 
+  - name: istioctl-zsh-completion-${{vars.major-minor-version}}
+    dependencies:
+      provides:
+        - istioctl-zsh-completion=${{package.full-version}}
+      runtime:
+        - istioctl-${{vars.major-minor-version}}
+    pipeline:
+      - runs: |
+          mkdir -p "${{targets.contextdir}}"/usr/share/zsh/site-functions
+          ${{targets.outdir}}/istioctl-${{vars.major-minor-version}}/usr/bin/istioctl completion zsh > "${{targets.contextdir}}"/usr/share/zsh/site-functions/istioctl-${{vars.major-minor-version}}
+    test:
+      pipeline:
+        - runs: stat /usr/share/zsh/site-functions/istioctl-${{vars.major-minor-version}}
+
   - name: istio-cni-${{vars.major-minor-version}}-compat
     pipeline:
       - runs: |