Also do not include jenkins pipeline in gem package

Author: MadsNielsen

Dockerfile

@@ -2,7 +2,6 @@ FROM ruby:2.5
 RUN ruby --version
 RUN apt-get update && \
     apt-get install cmake -y
-WORKDIR /tmp
 
 RUN gem install plusbump --pre
 

plusbump.gemspec

@@ -15,7 +15,7 @@ Gem::Specification.new do |spec|
   spec.license       = "MIT"
 
   spec.files         = `git ls-files -z`.split("\x0").reject do |f|
-    f.match(%r{^(test|spec|features)/})
+    f.match(%r{^(test|spec|features|jenkins-pipeline)/})
   end
 
   spec.bindir        = "bin"