Add quotes for unaffected versions

Hoping this makes some checker scripts happy

Author: reedloden

gems/strong_password/CVE-2019-13354.yml

@@ -13,4 +13,4 @@ description: |
   Downgrade `strong_password` to v0.0.6 to ensure no malicious code execution is possible.
 
 unaffected_versions:
-  - != 0.0.7
+  - "!= 0.0.7"