pkgng: test with zsh not bash package

Had been using bash package, because it's not
likely to disappear from the package repository
any time soon. Turns out that bash is already
installed on the Ansible community.general
FreeBSD CI VM image, which makes the test fail.

Zsh probably isn't going away any time soon,
either, and likely won't be installed on the
CI image.

tests/integration/targets/pkgng/tasks/main.yml

@@ -7,34 +7,34 @@
     ##
     ## pkgng - example - install single package
     ##
-    - name: Verify bash binary is not present
+    - name: Verify zsh binary is not present
       stat:
-        path: /usr/local/bin/bash
+        path: /usr/local/bin/zsh
         get_attributes: no
         get_checksum: no
         get_mime: no
       register: pkgng_example1_stat_before
 
-    - name: Install bash
+    - name: Install zsh
       pkgng:
-        name: bash
+        name: zsh
       register: pkgng_example1
 
-    - name: Remove bash (checkmode)
+    - name: Remove zsh (checkmode)
       pkgng:
-        name: bash
+        name: zsh
         state: absent
       check_mode: yes
       register: pkgng_example1_checkmode
 
-    - name: Install bash (idempotent)
+    - name: Install zsh (idempotent)
       pkgng:
-        name: bash
+        name: zsh
       register: pkgng_example1_idempotent
 
-    - name: Verify bash binary is present
+    - name: Verify zsh binary is present
       stat:
-        path: /usr/local/bin/bash
+        path: /usr/local/bin/zsh
         get_attributes: no
         get_checksum: no
         get_mime: no
@@ -51,7 +51,7 @@
           - pkgng_example1_stat_after.stat.executable
 
     ##
-    ## pkgng - example - Install bash in jail
+    ## pkgng - example - Install zsh in jail
     ##
     - name: Test within jail
       #
@@ -63,37 +63,37 @@
         - name: Setup testjail
           include: setup-testjail.yml
 
-        - name: Verify bash binary is not present
+        - name: Verify zsh binary is not present
           stat:
-            path: /usr/jails/testjail/usr/local/bin/bash
+            path: /usr/jails/testjail/usr/local/bin/zsh
             get_attributes: no
             get_checksum: no
             get_mime: no
           register: pkgng_example2_stat_before
 
-        - name: Install bash
+        - name: Install zsh
           pkgng:
-            name: bash
+            name: zsh
             jail: testjail
           register: pkgng_example2
 
-        - name: Remove bash (checkmode)
+        - name: Remove zsh (checkmode)
           pkgng:
-            name: bash
+            name: zsh
             state: absent
             jail: testjail
           check_mode: yes
           register: pkgng_example2_checkmode
 
-        - name: Install bash (idempotent)
+        - name: Install zsh (idempotent)
           pkgng:
-            name: bash
+            name: zsh
             jail: testjail
           register: pkgng_example2_idempotent
 
-        - name: Verify bash binary is present
+        - name: Verify zsh binary is present
           stat:
-            path: /usr/jails/testjail/usr/local/bin/bash
+            path: /usr/jails/testjail/usr/local/bin/zsh
             get_attributes: no
             get_checksum: no
             get_mime: no