*: add challenge-bot.yml and address review comments

Signed-off-by: Neil Shen <overvenus@gmail.com>

.github/challenge-bot.yml

@@ -0,0 +1 @@
+defaultSigLabel: sig/migrate

go.mod1

@@ -54,6 +54,7 @@ require (
 	sourcegraph.com/sourcegraph/appdash v0.0.0-20190731080439-ebfcffb1b5c0
 )
 
+// The fork updates BR dependency in order to fix `make build`. It can be removed once we updates BR dependency in TiDB.
 replace github.com/pingcap/tidb-lightning => github.com/overvenus/tidb-lightning v5.0.0-rc.0.20210129142610-fe7a7a431b0c+incompatible
 
 replace cloud.google.com/go/storage => github.com/3pointer/google-cloud-go/storage v1.6.1-0.20210108125931-b59bfa0720b2

tests/_utils/run_sql

@@ -23,5 +23,5 @@ mysql -uroot -h127.0.0.1 -P4000 \
     --ssl-ca="$TEST_DIR/certs/ca.pem" \
     --ssl-cert="$TEST_DIR/certs/curl.pem" \
     --ssl-key="$TEST_DIR/certs/curl.key" \
-    $@ \
+    "$@" \
     --default-character-set utf8 -E -e "$SQL" | tee -a "$TEST_DIR/sql_res.$TEST_NAME.txt"

tests/run.sh

@@ -20,7 +20,7 @@ export TEST_DIR=/tmp/backup_restore_test
 # Reset TEST_DIR
 rm -rf $TEST_DIR && mkdir -p $TEST_DIR
 
-# Generate TSL certs
+# Generate TLS certs
 tests/_utils/generate_certs &> /dev/null
 
 SELECTED_TEST_NAME="${TEST_NAME-$(find tests -mindepth 2 -maxdepth 2 -name run.sh | cut -d/ -f2 | sort)}"