allow extracting CVEs from stdin

[ryran]

We could also allow for finding CVEs in stdin, e.g., cat somefile.csv | rhsecapi which would use a regex like CVE-[0-9]{4}-[0-9]{4,} to pull out any CVE numbers ...

[ryran]

DONE!

$ rhsecapi --help | grep -A4 stdin
  -s, --extract-stdin   Extract CVEs from stdin (CVEs will be matched by regex
                        'CVE-[0-9]{4}-[0-9]{4,}' and duplicates will be
                        discarded); note that auto-detection of terminal width
                        is not possible in this mode and defaults to a width
                        of '70' (this can be overridden with '--width' option)

[ryran]

DONE!

$ rhsecapi --help | grep -A4 stdin
  -s, --extract-stdin   Extract CVEs from stdin (CVEs will be matched by regex
                        'CVE-[0-9]{4}-[0-9]{4,}' and duplicates will be
                        discarded); note that auto-detection of terminal width
                        is not possible in this mode and defaults to a width
                        of '70' (this can be overridden with '--width' option)