contrib: update vpx to v1.10.0

Change-Id: I38758678eb3af510307850ab03f7eb66ae448432

contrib/src/vpx/SHA512SUMS

-615476a929e46befdd4782a39345ce55cd30176ecb2fcd8a875c31694ae2334b395dcab9c5ba58d53ceb572ed0c022d2a3748ca4bbd36092e22b01cf3c9b2e8e  libvpx-v1.8.1.tar.gz
+f88c588145b5164e98531b75215e119056cd806a9dbe6599bb9dab35c0af0ecd4b3daabee7d795e412a58aeb543d5c7dc0107457c4bd8f4d434e966e8e22a32d  libvpx-v1.10.0.tar.gz
\ No newline at end of file

contrib/src/vpx/rules.mak

 # libvpx
 
-VPX_HASH := v1.8.1
+VPX_HASH := v1.10.0
 VPX_URL := https://github.com/webmproject/libvpx/archive/$(VPX_HASH).tar.gz
 
 $(TARBALLS)/libvpx-$(VPX_HASH).tar.gz:
@@ -55,11 +55,8 @@ VPX_OS := darwin
 else ifeq ($(ARCH),arm64)
 VPX_OS := darwin
 else
-ifeq ($(OSX_VERSION),10.5)
-VPX_OS := darwin9
-else
-VPX_OS := darwin10
-endif
+#to support minimum macOS version 10.13
+VPX_OS := darwin17
 endif
 else ifdef HAVE_SOLARIS
 VPX_OS := solaris