Update test matrix to use 8.15.3 (#868)

* Update test matrix to use 8.15.3

* Apply workaround to force install synthetics for 8.15.3

* Fix fleet setup for test for 8.15.3

---------

Co-authored-by: Boris Ilyushonak <[email protected]>

Author: dimuon

.github/workflows/test.yml

@@ -123,7 +123,7 @@ jobs:
           - '8.12.2'
           - '8.13.4'
           - '8.14.3'
-          - '8.15.0'
+          - '8.15.3'
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
       - uses: actions/setup-go@41dfa10bad2bb2ae585af6ee5bb4d7d973ad74ed # v5
@@ -153,7 +153,7 @@ jobs:
 
       - id: setup-fleet
         name: Setup Fleet
-        if: matrix.version == '8.10.3' || matrix.version == '8.11.4' || matrix.version == '8.12.2' || matrix.version == '8.13.4' || matrix.version == '8.14.3' || matrix.version == '8.15.0'
+        if: matrix.version == '8.10.3' || matrix.version == '8.11.4' || matrix.version == '8.12.2' || matrix.version == '8.13.4' || matrix.version == '8.14.3' || matrix.version == '8.15.3'
         run: |-
           make setup-kibana-fleet
         env:
@@ -162,7 +162,7 @@ jobs:
 
       - id: force-install-synthetics
         name: Force install synthetics
-        if: matrix.version == '8.14.3' || matrix.version == '8.15.0'
+        if: matrix.version == '8.14.3' || matrix.version == '8.15.3'
         run: |-
           for i in {1..5}; do curl -s -H "Authorization: ApiKey ${{ steps.get-api-key.outputs.apikey }}" --header "Content-Type: application/json" --header "kbn-xsrf: true" --request POST --data '{ "force": true }' http://localhost:5601/api/fleet/epm/packages/synthetics/1.2.2 && break || sleep 15; done