semaphore.sh: use Go 1.10

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

.semaphore.sh

@@ -10,7 +10,7 @@ fi
 docker run \
 	--rm \
 	--volume=`pwd`:/go/src/github.com/coreos/etcd \
-	gcr.io/etcd-development/etcd-test:go1.9.4 \
+	gcr.io/etcd-development/etcd-test:go1.10 \
 	/bin/bash -c "${TEST_OPTS} ./test 2>&1 | tee test-${TEST_SUFFIX}.log"
 
 ! egrep "(--- FAIL:|panic: test timed out|appears to have leaked)" -B50 -A10 test-${TEST_SUFFIX}.log