Bump version to 2.28.9

Soversions unchanged.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/include/mbedtls/version.h b/include/mbedtls/version.h
index bbe76b1..66998bf 100644
--- a/include/mbedtls/version.h
+++ b/include/mbedtls/version.h
@@ -26,16 +26,16 @@
  */
 #define MBEDTLS_VERSION_MAJOR  2
 #define MBEDTLS_VERSION_MINOR  28
-#define MBEDTLS_VERSION_PATCH  8
+#define MBEDTLS_VERSION_PATCH  9
 
 /**
  * The single version number has the following structure:
  *    MMNNPP00
  *    Major version | Minor version | Patch version
  */
-#define MBEDTLS_VERSION_NUMBER         0x021C0800
-#define MBEDTLS_VERSION_STRING         "2.28.8"
-#define MBEDTLS_VERSION_STRING_FULL    "Mbed TLS 2.28.8"
+#define MBEDTLS_VERSION_NUMBER         0x021C0900
+#define MBEDTLS_VERSION_STRING         "2.28.9"
+#define MBEDTLS_VERSION_STRING_FULL    "Mbed TLS 2.28.9"
 
 #if defined(MBEDTLS_VERSION_C)