l10n: zh_CN: Update Git Glossary: pickaxe

Translate the term "pickaxe" as "挖掘".

Initially proposed by @louy2 .

Signed-off-by: Ray Chen <oldsharp@gmail.com>
diff --git a/po/zh_CN.po b/po/zh_CN.po
index 752937e..8a95d83 100644
--- a/po/zh_CN.po
+++ b/po/zh_CN.po
@@ -83,7 +83,7 @@
 #   patch                            |  补丁
 #   pathspec                         |  路径规格
 #   pattern                          |  模式
-#   pickaxe                          |  pickaxe
+#   pickaxe                          |  挖掘
 #   plumbing                         |  管件(Git 底层核心命令的别称)
 #   porcelain                        |  瓷件(Git 上层封装命令的别称)
 #   prune                            |  清除