Use CentOS 7.3 in the Test Kitchen configs

lib/chef-dk/skeletons/code_generator/files/default/build_cookbook/.kitchen.yml

@@ -12,7 +12,7 @@ provisioner:
 
 platforms:
   - name: ubuntu-16.04
-  - name: centos-7.2
+  - name: centos-7.3
 
 suites:
   - name: default

lib/chef-dk/skeletons/code_generator/templates/default/kitchen.yml.erb

@@ -14,7 +14,7 @@ verifier:
 
 platforms:
   - name: ubuntu-16.04
-  - name: centos-7.2
+  - name: centos-7.3
 
 suites:
   - name: default

lib/chef-dk/skeletons/code_generator/templates/default/kitchen_policyfile.yml.erb

@@ -23,7 +23,7 @@ verifier:
 
 platforms:
   - name: ubuntu-16.04
-  - name: centos-7.2
+  - name: centos-7.3
 
 suites:
   - name: default

omnibus/.kitchen.yml

@@ -30,7 +30,7 @@ provisioner:
 platforms:
   - name: centos-6.7
     run_list: yum-epel::default
-  - name: centos-7.2
+  - name: centos-7.3
     run_list: yum-epel::default
   - name: debian-7.9
     run_list: apt::default

spec/unit/command/generator_commands/cookbook_spec.rb

@@ -572,7 +572,7 @@ def with_argv(argv)
 
 platforms:
   - name: ubuntu-16.04
-  - name: centos-7.2
+  - name: centos-7.3
 
 suites:
   - name: default
@@ -647,7 +647,7 @@ def with_argv(argv)
 
 platforms:
   - name: ubuntu-16.04
-  - name: centos-7.2
+  - name: centos-7.3
 
 suites:
   - name: default