Replace the LICENSE link with mit.LICENSE

This makes the license text properly show up at [1]. Apparently
GitHub's logic is not able to follow symbolic links here.

[1]: https://github.com/package-url/purl-spec?tab=License-1-ov-file#readme

Signed-off-by: Sebastian Schuberth <[email protected]>
Signed-off-by: Sebastian Schuberth <[email protected]>

Author: pombredanne

LICENSE

@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: MIT
+# Copyright (c) the purl authors
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy of
+# this software and associated documentation files (the "Software"), to deal in
+# the Software without restriction, including without limitation the rights to
+# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+# the Software, and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+# Visit https://github.com/package-url/purl-spec and https://packageurl.org for support