Reformat vulnerability report, add url field

text/0000-security-advisories.md

@@ -86,7 +86,6 @@ A correct invocation makes Cargo do the following:

   ```
   [vulnerability]
   # Edit this as you wish
   package = "mypackage"
   versions = ["1.2.0", "1.2.3", "1.2.4", "1.2.5"]

@@ -98,9 +97,12 @@ A correct invocation makes Cargo do the following:
   # dwf = "CVE-YYYY-XXXX"
   # dwf = ["CVE-YYYY-XXXX", "CVE-ZZZZ-WWWW"]

   # URL to a long-form description of this issue, e.g. a blogpost announcing
   # the release or a changelog entry (optional)
   url = false

   # Enter a short-form description of the vulnerability here. Preferrably a
   # single paragraph.
   # single paragraph (required)
   description = """
   
   """