Update COPYRIGHT.txt

update license

COPYRIGHT.txt

@@ -1,18 +1,17 @@
 Expansion Hunter
 Copyright (c) 2016 Illumina, Inc.
 
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-at your option) any later version.
+This program is licensed under the PolyForm Strict License 1.0.0
+you may not use the software except in compliance with the License.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
+PolyForm Strict License 1.0.0 for more details.
 
-You should have received a copy of the GNU General Public License
-along with this program.  If not, see <http://www.gnu.org/licenses/>.
+You should have received a copy of the PolyForm Strict License 1.0.0
+along with this program.  
+If not, see https://polyformproject.org/licenses/strict/1.0.0
 
 
 ******************************************************************
@@ -258,4 +257,4 @@ 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.
+THE SOFTWARE.