*: fix license (tikv#10318)

* *: fix license

The text is not in correct format and I copy one from
https://www.apache.org/licenses/LICENSE-2.0.txt.

Signed-off-by: Jay Lee <BusyJayLee@gmail.com>

* fix misleading license template

Signed-off-by: Jay Lee <BusyJayLee@gmail.com>

Co-authored-by: Ti Chi Robot <ti-community-prow-bot@tidb.io>

Author: BusyJay

LICENSE

@@ -1,4 +1,4 @@
-Apache License
+                                 Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/
 
@@ -178,15 +178,15 @@ Apache License
    APPENDIX: How to apply the Apache License to your work.
 
       To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "{}"
+      boilerplate notice, with the fields enclosed by brackets "[]"
       replaced with your own identifying information. (Don't include
       the brackets!)  The text should be enclosed in the appropriate
       comment syntax for the file format. We also recommend that a
       file or class name and description of purpose be included on the
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright {}
+   Copyright [yyyy] [name of copyright owner]
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

license.template etc/license.template

@@ -2,7 +2,7 @@ version = "Two"
 unstable_features = true
 
 condense_wildcard_suffixes = true
-license_template_path = "license.template"
+license_template_path = "etc/license.template"
 newline_style = "Unix"
 use_field_init_shorthand = true
 use_try_shorthand = true