adjusting Changelog entry for PR #4094

Signed-off-by: Daniel Otte <d.otte@wut.de>
diff --git a/ChangeLog.d/issue4093.txt b/ChangeLog.d/issue4093.txt
index 8f6e8f7..f6985cf 100644
--- a/ChangeLog.d/issue4093.txt
+++ b/ChangeLog.d/issue4093.txt
@@ -1,6 +1,6 @@
-Bugfix
-   * Fix an errorneous estimation for an internal buffer in 
+Security
+   * Fix an errorneous estimation for an internal buffer in
      mbedtls_pk_write_key_pem(). If MBEDTLS_MPI_MAX_SIZE is set to an odd
      value the function might fail to write a private RSA keys of the largest
      supported size.
-     Found by Daniel Otte in #4093 and fixed in #4094.
\ No newline at end of file
+     Found by Daniel Otte, reported in #4093 and fixed in #4094.