manifest: Use tools/repohooks master branch

All master has over android10-release is py3 compat and a bunch
of formatting and UTF-8 fixes

Change-Id: I05f6bd5b4f4fcd6fd703e332ac2168aa9679bd2a

default.xml

@@ -673,7 +673,7 @@
   <project path="tools/metalava" name="platform/tools/metalava" groups="pdk,tools" remote="aosp" />
   <project path="tools/motodev" name="platform/tools/motodev" groups="notdefault,motodev" remote="aosp" />
   <project path="tools/ndkports" name="platform/tools/ndkports" groups="pdk" remote="aosp" />
-  <project path="tools/repohooks" name="platform/tools/repohooks" groups="adt-infra,cts,developers,motodev,pdk,tools,tradefed" remote="aosp" />
+  <project path="tools/repohooks" name="platform/tools/repohooks" groups="adt-infra,cts,developers,motodev,pdk,tools,tradefed" remote="aosp" revision="master" />
   <project path="tools/security" name="platform/tools/security" groups="pdk,tools" remote="aosp" />
   <project path="tools/studio/cloud" name="platform/tools/studio/cloud" groups="notdefault,tools" remote="aosp" />
   <project path="tools/swt" name="platform/tools/swt" groups="notdefault,tools" remote="aosp" />