MAINT: add codecov commenter bot

.github/codecov.yml

@@ -0,0 +1,12 @@
+codecov:
+  require_ci_to_pass: false
+
+coverage:
+  precision: 2
+  round: down
+  range: "70...100"
+  status:
+    project:
+      default:
+        target: 70%    # the required coverage value
+        threshold: 1%  # the leniency in hitting the target

.github/workflows/gradle.yml

@@ -28,3 +28,5 @@ jobs:
       run: chmod +x gradlew
     - name: Build with Gradle
       run: ./gradlew build
+    - name: Upload Coverage Report
+      uses: codecov/codecov-action@v1

README.md

@@ -1,4 +1,4 @@
-
+[![codecov](https://codecov.io/gh/opensearch-project/data-prepper/branch/main/graph/badge.svg?token=IS7GOIY622)](https://codecov.io/gh/opensearch-project/data-prepper)
 # Data Prepper
 
 We envision Data Prepper as an open source data collector for observability data (trace, logs, metrics) that can filter, enrich, transform, normalize, and aggregate data for downstream analysis and visualization. It will support stateful processing across multiple instances of data pipelines for observability use cases such as distributed tracing and multi-line log events (e.g. stack traces, aggregations, and log-to-metric transformations). Currently Data Prepper supports processing of distributed trace data and will support processing of logs and metric data in the future. 

build.gradle

@@ -84,6 +84,9 @@ subprojects {
     build.dependsOn test
     jacocoTestReport {
         dependsOn test // tests are required to run before generating the report
+        reports {
+            xml.enabled true
+        }
     }
 
     task allDeps(type: DependencyReportTask) {}
@@ -101,7 +104,7 @@ configure(coreProjects) {
     jacocoTestReport {
         dependsOn test // tests are required to run before generating the report
         reports {
-            xml.enabled false
+            xml.enabled true
             csv.enabled false
             html.destination file("${buildDir}/reports/jacocoHtml")
         }

data-prepper-plugins/opensearch/build.gradle

@@ -132,6 +132,9 @@ integTest {
 
 jacocoTestReport {
     dependsOn test
+    reports {
+        xml.enabled true
+    }
     afterEvaluate {
         classDirectories.from = files(classDirectories.files.collect {
             fileTree(dir: it, exclude: [