Refactor: simpler way to extract postgres major version

Author: qount25

lib/pgpm/deb/spec.rb

@@ -12,7 +12,7 @@ class Spec
       def initialize(package)
         @postgres_distribution = Pgpm::Postgres::Distribution.in_scope
         @package = package
-        @package.postgres_major_version = @postgres_distribution.version.split(".")[0]
+        @package.postgres_major_version = @postgres_distribution.major_version
         @package.os = "debian"
         @release = 1
       end

lib/pgpm/rpm/spec.rb

@@ -17,7 +17,7 @@ def initialize(package)
         # version of postgres and selected OS.
         @package = package
         @package.os = "redhat"
-        @package.postgres_major_version = @postgres_distribution.version.split(".")[0]
+        @package.postgres_major_version = @postgres_distribution.major_version
       end
 
       def versionless