Add changelog entry for non-uniform MPI random generation

Fix #4245.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/random-range.txt b/ChangeLog.d/random-range.txt
new file mode 100644
index 0000000..dc35ec6
--- /dev/null
+++ b/ChangeLog.d/random-range.txt
@@ -0,0 +1,4 @@
+Security
+* Fix a bias in the generation of finite-field Diffie-Hellman-Merkle (DHM)
+  private keys and of blinding values for DHM and elliptic curves (ECP)
+  computations. Reported by FlorianF89 in #4245.