Fix links to fingerprint verification sources in README

Author: defuse

README.md

@@ -108,7 +108,7 @@ The GnuPG public key used to sign the current and new releases is available in
 
 You can verify it against Taylor Hornby's [contact
 page](https://defuse.ca/contact.htm) and
-[twitter](https://twitter.com/DefuseSec/status/723741424253059074).
+[twitter](https://twitter.com/DefuseSec/status/1670840796743081984).
 
 Older releases were signed with a (now-expired) available in
 [dist/signingkey-old.asc](https://github.com/defuse/php-encryption/raw/master/dist/signingkey-old.asc). The old key's fingerprint is:
@@ -117,5 +117,8 @@ Older releases were signed with a (now-expired) available in
 2FA6 1D8D 99B9 2658 6BAC  3D53 385E E055 A129 1538
 ```
 
+The old key's fingerprint can be verified against Taylor Hornby's [contact page](https://defuse.ca/contact.htm) and
+[twitter](https://twitter.com/DefuseSec/status/723741424253059074).
+
 A signature of this new key by the old key is available in
 [dist/signingkey-new.asc.sig](https://github.com/defuse/php-encryption/raw/master/dist/signingkey-new.asc.sig).