Update library version to 2.18.0

Increase the SO versions of libmbedx509 and libmbedtls due to the
addition of fields in publicly visible (non-opaque) structs:
  - mbedtls_ssl_config
  - mbedtls_ssl_context
  - mbedtls_x509_crt
diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 1004cb3..ea069ab 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -172,14 +172,14 @@
 if(USE_SHARED_MBEDTLS_LIBRARY)
 
     add_library(mbedx509 SHARED ${src_x509})
-    set_target_properties(mbedx509 PROPERTIES VERSION 2.17.0 SOVERSION 0)
+    set_target_properties(mbedx509 PROPERTIES VERSION 2.18.0 SOVERSION 1)
     target_link_libraries(mbedx509 ${libs} mbedcrypto)
     target_include_directories(mbedx509
         PUBLIC ${CMAKE_SOURCE_DIR}/include/
         PUBLIC ${CMAKE_SOURCE_DIR}/crypto/include/)
 
     add_library(mbedtls SHARED ${src_tls})
-    set_target_properties(mbedtls PROPERTIES VERSION 2.17.0 SOVERSION 12)
+    set_target_properties(mbedtls PROPERTIES VERSION 2.18.0 SOVERSION 13)
     target_link_libraries(mbedtls ${libs} mbedx509)
     target_include_directories(mbedtls
         PUBLIC ${CMAKE_SOURCE_DIR}/include/
diff --git a/library/Makefile b/library/Makefile
index 60f3ae0..89c4128 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -35,8 +35,8 @@
 endif
 endif
 
-SOEXT_TLS=so.12
-SOEXT_X509=so.0
+SOEXT_TLS=so.13
+SOEXT_X509=so.1
 SOEXT_CRYPTO=so.3
 
 # Set AR_DASH= (empty string) to use an ar implementation that does not accept