Use f-strings for better readability

[johnmhoran]

From @tdruez 's comments in https://github.com/nexB/vulnerablecode/issues/875 .

Use f-strings for better readability:

search_string = request.GET["name"]
"package_search": f"The VCIO DB does not contain a record of the package you entered: {search_string}."

[35C4n0r]

@johnmhoran can i work on this issue?

[johnmhoran]

Thanks @35C4n0r but I have this covered -- I'm working on all the UI issues.