Added ChangeLog entry for related issue.

Signed-off-by: ENT\stroej1 <john.stroebel@medtronic.com>
diff --git a/ChangeLog.d/issue3819.txt b/ChangeLog.d/issue3819.txt
new file mode 100644
index 0000000..927b6a2
--- /dev/null
+++ b/ChangeLog.d/issue3819.txt
@@ -0,0 +1,4 @@
+Bugfix
+   * Fix incorrect seed generation when a nonce is included
+     in mbedtls_ctr_drbg_reseed_internal.
+     Found by John Stroebel in #3819 and fixed in #3973.