dictionary_rare: add unsecure->insecure (#1496)

diff --git a/codespell_lib/data/dictionary_rare.txt b/codespell_lib/data/dictionary_rare.txt
index 4b85eef..b6dfa89 100644
--- a/codespell_lib/data/dictionary_rare.txt
+++ b/codespell_lib/data/dictionary_rare.txt
@@ -143,6 +143,7 @@
 trough->through
 unknow->unknown
 unknows->unknowns
+unsecure->insecure
 untypically->atypically
 vertexes->vertices
 vie->via