Correctly exclude 4.0.0.beta* from unaffected_versions (closes #151).

* This will match versions `3.X.X` as unaffected, but still flag
  versions `4.0.0.beta1` and `4.0.0.beta2` as affected.

Author: postmodern

gems/passenger/CVE-2012-6135.yml

@@ -14,6 +14,6 @@ description: |
 cvss_v2: 2.1
 cvss_v3: 7.5
 unaffected_versions:
-  - "< 4.0.0"
+  - "< 4.0.0.beta"
 patched_versions:
   - ">= 4.0.0"