Add ubuntu gfx908 target to CI

[ROCm/rccl commit: 25a7dad765]

projects/rccl/.jenkins/precheckin.groovy

@@ -55,7 +55,7 @@ ci: {
 
     propertyList = auxiliary.appendPropertyList(propertyList)
 
-    def jobNameList = ["compute-rocm-dkms-no-npi-hipclang":([sles15sp1:['4gfx906'],centos8:['4gfx908'],centos7:['4gfx906'],ubuntu18:['4gfx906']])]
+    def jobNameList = ["compute-rocm-dkms-no-npi-hipclang":([sles15sp1:['4gfx906'],centos8:['4gfx908'],centos7:['4gfx906'],ubuntu18:['4gfx906', '4gfx908']])]
     
     jobNameList = auxiliary.appendJobNameList(jobNameList)