build: add go120 build for win7/8.1

.github/rename-go120.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+FILENAMES=$(ls)
+for FILENAME in $FILENAMES
+do
+    if [[ ! ($FILENAME =~ ".exe" || $FILENAME =~ ".sh")]];then
+        mc $FILENAME ${FILENAME}-go120
+    elif [[ $FILENAME =~ ".exe" ]];then
+        mv $FILENAME ${FILENAME%.*}-go120.exe
+    else echo "skip $FILENAME"
+    fi
+done