ci: fix coverage reports (#3709)

Author: noomorph

.buildkite/pipeline.post_processing.yml

@@ -0,0 +1,8 @@
+  - wait: ~
+    continue_on_failure: true
+  - label: "Post-processing: Test coverage"
+    command:
+      - "nvm install"
+      - "mkdir -p aggregated-coverage"
+      - "buildkite-agent artifact download '**/*.lcov' aggregated-coverage"
+      - "bash scripts/aggregate_coverage.sh"

.buildkite/pipeline_common.sh

@@ -10,3 +10,4 @@ cat .buildkite/jobs/pipeline.android_demo_app_rn_68.yml
 cat .buildkite/jobs/pipeline.android_demo_app_rn_69.yml
 cat .buildkite/jobs/pipeline.ios_demo_app_rn_68.yml
 cat .buildkite/jobs/pipeline.ios_demo_app_rn_69.yml
+cat .buildkite/pipeline.post_processing.yml