chore: remove `Jenkinsfile` (#23)

Jenkinsfile

@@ -1,21 +0,0 @@
-node {
-    checkout scm
-}
-
-pipeline {
-    agent any
-
-    stages {
-        stage('Build') {
-            steps {
-                sh "make build-test"
-            }
-        }
-        stage('Test') {
-            steps {
-                sh "make test"
-                recordCoverage(tools: [[parser: 'COBERTURA', pattern: 'docker/test/coverage.xml']])
-            }
-        }
-    }
-}