Jenkins: use build library from proper branch "equuleus"

Jenkinsfile

@@ -1,4 +1,4 @@
-// Copyright (C) 2020 VyOS maintainers and contributors
+// Copyright (C) 2020-2021 VyOS maintainers and contributors
 //
 // This program is free software; you can redistribute it and/or modify
 // in order to easy exprort images built to "external" world
@@ -12,13 +12,12 @@
 //
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
 @NonCPS
 
 // Using a version specifier library, use 'current' branch. The underscore (_)
 // is not a typo! You need this underscore if the line immediately after the
 // @Library annotation is not an import statement!
-@Library('vyos-build@current')_
+@Library('vyos-build@equuleus')_
 
-// Start package build using library function from https://github.com/c-po/vyos-build
+// Start package build using library function from https://github.com/vyos/vyos-build
 buildPackage()