Extend key ID matching to expired keys

gpg accepts signatures with expired keys as long as the signature was
made prior to key expiration. But it also changes the status-fd output
format that we grep for the expected key ID. Make sure we look for the
alternate EXPKEYSIG line in the output in that case to find the key ID.

autospec/specfiles.py

@@ -159,6 +159,9 @@ class Specfile(object):
 
         # if package is verified, include the signature in the source tarball
         if self.keyid and self.config.signature:
+            # We'll need gnupg to verify the signature. Need to add it here so it's ready before write_buildreq
+            self.requirements.add_buildreq("gnupg")
+
             count += 1
             self._write_strip(f"Source{count}  : {self.config.signature}")
             self.config.signature_macro = f"%{{SOURCE{count}}}"
@@ -441,7 +444,7 @@ class Specfile(object):
             self._write_strip("chmod 700 .gnupg")
             self._write_strip(f"gpg --homedir .gnupg --import {self.config.pkey_macro}")
             self._write_strip(f"gpg --homedir .gnupg --status-fd 1 --verify {self.config.signature_macro} %{{SOURCE0}} > gpg.status")
-            self._write_strip(f"grep '^\\[GNUPG:\\] GOODSIG {self.keyid}' gpg.status")
+            self._write_strip(f"grep -E '^\\[GNUPG:\\] (GOODSIG|EXPKEYSIG) {self.keyid}' gpg.status")
         self.write_prep_prepend()
         prefix = self.content.prefixes[self.url]
         if self.config.default_pattern == 'R':