license: Add legal notice regarding California and Colorado bills

As a consequence of recent legislative activity in [California][cal]
and [Colororado][col]:

* California residents may no longer use DB48x after Jan 1st, 2027.
* Colorado residents may no longer use DB48x after Jan 1st, 2028.

DB48x is probably an operating system under these laws. However, it
does not, cannot and will not implement age verification.

[cal]: https://leginfo.legislature.ca.gov/faces/billTextClient.xhtml?bill_id=202520260AB1043
[col]: https://leg.colorado.gov/bill_files/111670/download

Signed-off-by: Christophe de Dinechin <christophe@dinechin.org>

Author: c3d

LEGAL-NOTICE.md

@@ -0,0 +1,13 @@
+# Important notice to residents of California and Colorado
+
+As a consequence of recent legislative activity in [California][cal]
+and [Colororado][col]:
+
+* California residents may no longer use DB48x after Jan 1st, 2027.
+* Colorado residents may no longer use DB48x after Jan 1st, 2028.
+
+DB48x is probably an operating system under these laws. However, it
+does not, cannot and will not implement age verification.
+
+[cal]: https://leginfo.legislature.ca.gov/faces/billTextClient.xhtml?bill_id=202520260AB1043
+[col]: https://leg.colorado.gov/bill_files/111670/download