_scripts: upgrade to python3 (#3716)

Upgrade python script to python3

_scripts/latestver.py

@@ -1,6 +1,6 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 import json
-import urllib
+import urllib.request
 import sys
 import re
 
@@ -19,9 +19,9 @@ def splitver(x):
 	return v
 
 ver = sys.argv[1]
-d = json.loads(urllib.urlopen('https://go.dev/dl/?mode=json&include=all').read())
+d = json.loads(urllib.request.urlopen('https://go.dev/dl/?mode=json&include=all').read())
 ds = sorted(d, reverse=True, key=lambda it: splitver(it['version'][2:]))
 for x in ds:
 	if x['version'][:len(ver)] == ver:
-		print x['version']
+		print(x['version'])
 		exit(0)

_scripts/test_mac.sh

@@ -25,7 +25,7 @@ if [ "$GOVERSION" = "gotip" ]; then
     cd -
 else
     echo Finding latest patch version for $GOVERSION
-    GOVERSION=$(python _scripts/latestver.py $GOVERSION)
+    GOVERSION=$(python3 _scripts/latestver.py $GOVERSION)
     echo Go $GOVERSION on $ARCH
     cd $TMPDIR
     curl -sSL "https://storage.googleapis.com/golang/$GOVERSION.darwin-$ARCH.tar.gz" | tar -xz