[InterNetNews/inn] 22c484: Recommend GnuPG prior to 2.1.0 in INSTALL

[Russ Allbery]

  Branch: refs/heads/main
  Home:   https://github.com/InterNetNews/inn
  Commit: 22c4844c53ee1f2792d3db85f1e934c523dab43a
      https://github.com/InterNetNews/inn/commit/22c4844c53ee1f2792d3db85f1e934c523dab43a
  Author: Russ Allbery <eagle at eyrie.org>
  Date:   2022-05-31 (Tue, 31 May 2022)

  Changed paths:
    M doc/pod/install.pod

  Log Message:
  -----------
  Recommend GnuPG prior to 2.1.0 in INSTALL

Mention that verifying some control messages requires an older
version of GnuPG, and point to the gnupg1 package.  Mention the
--allow-weak-digest-algos flag when importing keys.