Sorry, what's the problem here? Have you changed your gpg key?
$ gpg --recv 698F1519
gpg: requesting key 698F1519 from hkp server keyserver.cns.vt.edu
gpg: key 698F1519: "Dave Page <dpage@pgadmin.org>" not changed
gpg: key 698F1519: "Dave Page <dpage@pgadmin.org>" not changed
gpg: Total number processed: 2
gpg: unchanged: 2
$ gpg --verify pgadmin4-1.3.dmg.sig pgadmin4-1.3.dmg
gpg: Signature made Tue Mar 7 07:22:31 2017 EST using RSA key ID 698F1519
gpg: Good signature from "Dave Page <dpage@pgadmin.org>" [unknown]
gpg: aka "Dave Page <pgsnake@gmail.com>" [unknown]
gpg: aka "Dave Page <dpage@postgresql.org>" [unknown]
gpg: aka "Dave Page <dave.page@enterprisedb.com>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: E0C4 CEEB 826B 1FDA 4FB4 68E0 24AD FAAF 698F 1519