[misc] Set signing env only if not fork and set license (#5659)

* Add condition to GPG key decoding to handle pull requests

* Add license field to deb and rpm package configurations

* Add condition to GPG key decoding for external pull requests

.goreleaser.yaml

@@ -171,6 +171,7 @@ nfpms:
   - maintainer: Netbird <dev@netbird.io>
     description: Netbird client.
     homepage: https://netbird.io/
+    license: BSD-3-Clause
     id: netbird_deb
     bindir: /usr/bin
     builds:
@@ -184,6 +185,7 @@ nfpms:
   - maintainer: Netbird <dev@netbird.io>
     description: Netbird client.
     homepage: https://netbird.io/
+    license: BSD-3-Clause
     id: netbird_rpm
     bindir: /usr/bin
     builds: