README: Fix wrong URLs.

build.sh

@@ -65,7 +65,7 @@ build() {
     [ $CORES -eq 0 ] && CORES=2
 
     for a in ${TARGET_ABI_LIST[@]}; do
-        echo "Building $a artifacts... Using $CORES  thread."
+        echo "Building $a artifacts... Using $CORES thread."
         cmake --build build_$a -j$CORES
         echo "$a build complete, artifacts: $PWD/build_$a"
     done