Fix reusable workflow configuration

- Add workflow_call trigger to check-version.yml, lint.yml, and test.yml
- Enable these workflows to be called by ci.yml as reusable workflows
- Resolve GitHub Actions workflow validation error

Author: locus313

.github/workflows/check-version.yml

@@ -8,6 +8,7 @@ on:
       - 'sync-ssh-keys.sh'
       - 'users.conf'
       - '.github/workflows/check-version.yml'
+  workflow_call:
 
 jobs:
   check-version:

.github/workflows/lint.yml

@@ -15,6 +15,7 @@ on:
       - 'sync-ssh-keys.sh'
       - 'users.conf'
       - '.github/workflows/lint.yml'
+  workflow_call:
 
 jobs:
   shellcheck:

.github/workflows/test.yml

@@ -18,6 +18,7 @@ on:
       - 'sync-ssh-keys.sh'
       - 'users.conf'
       - '.github/workflows/test.yml'
+  workflow_call:
 
 jobs:
   test: