Use . for sourcing env files as the POSIX compliant command

Author: iangmaia

lib/fastlane/plugin/wpmreleasetoolkit/actions/common/buildkite_pipeline_upload_action.rb

@@ -21,7 +21,9 @@ def self.run(params)
         if env_file && File.exist?(env_file)
           UI.message(" - Sourcing environment file beforehand: #{env_file}")
 
-          sh(environment, "source #{env_file.shellescape} && buildkite-agent pipeline upload #{pipeline_file.shellescape}")
+          # Use `.` instead of `source` for POSIX compliance - works across all shells (sh/dash/bash/zsh)
+          # while `source` isn't always present
+          sh(environment, ". #{env_file.shellescape} && buildkite-agent pipeline upload #{pipeline_file.shellescape}")
         else
           sh(environment, 'buildkite-agent', 'pipeline', 'upload', pipeline_file)
         end

spec/buildkite_pipeline_upload_action_spec.rb

@@ -60,7 +60,7 @@
       allow(File).to receive(:exist?).with(env_file).and_return(true)
       expect(Fastlane::Action).to receive(:sh).with(
         environment,
-        "source #{env_file.shellescape} && buildkite-agent pipeline upload #{loaded_pipeline_file.shellescape}"
+        ". #{env_file.shellescape} && buildkite-agent pipeline upload #{loaded_pipeline_file.shellescape}"
       )
       expect_upload_pipeline_message
       expect_sourcing_env_file_message(env_file)
@@ -92,7 +92,7 @@
       allow(File).to receive(:exist?).with(env_file).and_return(true)
       expect(Fastlane::Action).to receive(:sh).with(
         environment_default,
-        "source #{env_file.shellescape} && buildkite-agent pipeline upload #{loaded_pipeline_file.shellescape}"
+        ". #{env_file.shellescape} && buildkite-agent pipeline upload #{loaded_pipeline_file.shellescape}"
       )
       expect_upload_pipeline_message
       expect_sourcing_env_file_message(env_file)
@@ -122,7 +122,7 @@
       allow(File).to receive(:exist?).with(env_file_default).and_return(true)
       expect(Fastlane::Action).to receive(:sh).with(
         environment_default,
-        "source #{env_file_default} && buildkite-agent pipeline upload #{loaded_pipeline_file.shellescape}"
+        ". #{env_file_default} && buildkite-agent pipeline upload #{loaded_pipeline_file.shellescape}"
       )
       expect_upload_pipeline_message
       expect_sourcing_env_file_message(env_file_default)