Added more info about PR prep to CONTRIBUTING.md file

CONTRIBUTING.md

@@ -1,14 +1,20 @@
 # Contributing Guidelines
 
 * Try to keep all text within 80 columns.
-* YAML must be indented by 2 spaces.
 * `title:` must be a single sentence/line.
 * `description: |` must contain more than one sentence/line.
 * `patched_versions`/`unaffected_versions` version ranges must be quoted
   (ex: `">= 1.2.3"`).
-* Please see the [README](README.md#schema) for more documentation on the
-  YAML Schema.
-* Prior to submitting a pull request, run the tests:
+* Values for 'cvss_v2', 'cvss_v3', and 'cvss_v4' can be found in
+  the reference URLs from nvd.nist.gov, https://github.com/advisories,
+  and the repo's security advisory.
+* Prior to submitting a pull request, 
+  * Run yamlint to check yaml format
+    * https://yamllint.readthedocs.io/en/stable
+    * YAML must be indented by 2 spaces.
+    * Please see the [README](README.md#schema) for more documentation on the
+      YAML Schema.
+  * Run the tests and see that it is clean:
 
 ```
 bundle install

spec/spec_helper.rb

@@ -1,3 +1,11 @@
+require 'strscan'
+
+class StringScanner
+  def peep(len)
+    peek(len)
+  end
+end
+
 require 'date'
 require 'kwalify'
 require 'rspec'