Update get_idf_ver.py

Author: Jason2866

tools/get_idf_ver.py

@@ -9,7 +9,7 @@ def main(ver_file_path):
         pattern = r"set\(IDF_VERSION_(MAJOR|MINOR|PATCH) (\d+)\)"
         matches = re.findall(pattern, fp.read())
         idf_version = str(".".join([match[1] for match in matches]))
-        idf_version = idf_version + str(datetime.date.today())
+        idf_version = idf_version + "." + str(datetime.date.today())
         os.environ["IDF_VERSION"] = idf_version
         return idf_version