Perform a shallow clone for the beats repo (#3928)

Signed-off-by: Alexandros Sapranidis <[email protected]>
Co-authored-by: Michal Pristas <[email protected]>

.buildkite/scripts/steps/beats_tests.sh

@@ -14,7 +14,7 @@ STACK_PROVISIONER="${1:-"serverless"}"
 run_test_for_beat(){
     export GOFLAGS='-buildvcs=false'
     local beat_name=$1
-    
+
     #build
     export WORKSPACE="/tmp/beats-build/beats/x-pack/${beat_name}"
     pushd $WORKSPACE
@@ -43,7 +43,7 @@ mage -l
 mkdir -p /tmp/beats-build
 pushd /tmp/beats-build
 
-git clone [email protected]:elastic/beats.git
+git clone --depth=1 [email protected]:elastic/beats.git
 popd
 
 # export WORKSPACE=beats/x-pack/metricbeat