add github workflows

Signed-off-by: Neetika Singhal <neetiks@amazon.com>

.github/workflows/concurrent-search.yml

@@ -0,0 +1,34 @@
+---
+name: Concurrent Search UTs and ITs
+
+on:
+  schedule:
+    - cron: '0 */4 * * *' # every 4 hours
+  workflow_dispatch: # on button click
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest]  # precommit on ubuntu-latest is run as a part of the gradle-check workflow
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK 11
+        if: always()
+        uses: actions/setup-java@v2
+        with:
+          java-version: 11
+          distribution: adopt
+      - name: Build the repo
+        if: always()
+        run: |
+          ./gradlew assemble -x :distribution:docker:buildArm64DockerImage -x :distribution:docker:buildDockerImage -x :distribution:docker:buildPpc64leDockerImage -x :distribution:docker:docker-export:exportDockerImage -x :distribution:docker:buildS390xDockerImage -x :distribution:docker:docker-ppc64le-export:exportDockerImage -x :distribution:docker:docker-s390x-export:exportDockerImage
+      - name: Run Gradle unit tests
+        if: always()
+        run: |
+          ./gradlew test -Dopensearch.experimental.feature.concurrent_segment_search.enabled=true
+      - name: Run Gradle integration tests
+        if: always()
+        run: |
+          ./gradlew internalClusterTest --parallel -Dopensearch.experimental.feature.concurrent_segment_search.enabled=true

.github/workflows/sync.yml

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+name: Sync Fork
+
+on:
+  schedule:
+    - cron: '0 */1 * * *' # every 1 hour
+  workflow_dispatch: # on button click
+
+jobs:
+  sync:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: tgymnich/fork-sync@v1.8
+        with:
+          token: ${{ secrets.PERSONAL_TOKEN }}
+          owner: neetikasinghal
+          base: main
+          head: main
+          merge_method: rebase