As VPP depends on the version of DPDK, in LSDK-20.04, DPDK was upgraded but VPP was not upgraded, so VPP was not required for test in LSDK2004, as a workaround , building VPP/DPDK lsdk1909 old version in flexbuild_lsdk1909 works.
We don't support VPP v20.01 and it was not claimed feature in LSDK2004 also.
But we are in process of supporting VPPv20.05 in LSDK2012 which will be released on Dec 15.