Update package_manager_is_valid.sh

Author: CLHatch

.scripts/package_manager_is_valid.sh

@@ -7,10 +7,10 @@ package_manager_is_valid() {
 
     local Old_IFS="${IFS}"
     IFS='|'
-    RegEx_PackageManagers="^(${PM_PACKAGE_MANAGERS[*]-})$"
+    RegEx_PackageManagers="(${PM_PACKAGE_MANAGERS[*]-})"
     IFS="${Old_IFS}"
 
-    [[ ${PackageManager} =~ ${RegEx_PackageManagers} ]]
+    [[ ${PackageManager} =~ ^${RegEx_PackageManagers}$ ]]
 }
 
 test_package_manager_is_valid() {