cmake: normalize version handling, introduce version.txt

As done in many other KDAB repos, store version in version.txt to
make it friendly for release tooling (release-plz and kdab release
scripts)

Author: iamsergio

CMakeLists.txt

@@ -58,12 +58,14 @@ project(
     LANGUAGES CXX
 )
 
-set(${PROJECT_NAME}_VERSION_MAJOR 2)
-set(${PROJECT_NAME}_VERSION_MINOR 2)
-set(${PROJECT_NAME}_VERSION_PATCH 95)
-set(${PROJECT_NAME}_VERSION
-    ${${PROJECT_NAME}_VERSION_MAJOR}.${${PROJECT_NAME}_VERSION_MINOR}.${${PROJECT_NAME}_VERSION_PATCH}
-)
+file(STRINGS version.txt KDSOAP_VERSION_FILE)
+list(GET KDSOAP_VERSION_FILE 0 ${PROJECT_NAME}_VERSION)
+
+string(REPLACE "." ";" KDSOAP_VERSION_LIST "${${PROJECT_NAME}_VERSION}")
+list(GET KDSOAP_VERSION_LIST 0 ${PROJECT_NAME}_VERSION_MAJOR)
+list(GET KDSOAP_VERSION_LIST 1 ${PROJECT_NAME}_VERSION_MINOR)
+list(GET KDSOAP_VERSION_LIST 2 ${PROJECT_NAME}_VERSION_PATCH)
+
 set(PROJECT_VERSION ${${PROJECT_NAME}_VERSION}) #needed for ECM
 set(${PROJECT_NAME}_SOVERSION ${${PROJECT_NAME}_VERSION_MAJOR})
 

version.txt

@@ -0,0 +1 @@
+2.2.95