Use latest version of isGitRegionMatch (elastic#238)

* chore: use uppercase in the spec

* chore: use new version of the isGitRegionMatch step

.ci/Jenkinsfile

@@ -49,14 +49,15 @@ pipeline {
           repo: "[email protected]:elastic/${REPO}.git",
           credentialsId: "${JOB_GIT_CREDENTIALS}"
         )
-        // make sure the GIT variables are properly set for the isGitRegionMatch step
-        setEnvVar('GIT_PREVIOUS_COMMIT', "${env.GIT_PREVIOUS_SUCCESSFUL_COMMIT}")
         script {
           dir("${BASE_DIR}"){
             def regexps =[
               "^tests/agents/gherkin-specs/"
             ]
-            env.GHERKIN_SPECS_UPDATED = isGitRegionMatch(patterns: regexps)
+            env.GHERKIN_SPECS_UPDATED = isGitRegionMatch(
+              from: "${env.GIT_PREVIOUS_SUCCESSFUL_COMMIT}",
+              to: "${env.GIT_COMMIT}",
+              patterns: regexps)
           }
         }
         stash allowEmpty: true, name: 'source', useDefaultExcludes: false

tests/agents/gherkin-specs/api_key.feature

@@ -1,11 +1,11 @@
 Feature: API Key
 
-  Scenario: A configured api key is sent in the Authorization header
+  Scenario: A configured API key is sent in the Authorization header
     Given an agent
     When an api key is set to 'RTNxMjlXNEJt' in the config
     Then the Authorization header is 'ApiKey RTNxMjlXNEJt'
 
-  Scenario: A configured api key takes precedence over a secret token
+  Scenario: A configured API key takes precedence over a secret token
     Given an agent
     When an api key is set to 'MjlXNEJasdfDt' in the config
     And a secret_token is set to 'secr3tT0ken' in the config