Revert "build: Update .so versioning to x.y format"

This reverts commit 2c8b00e.

Author: xnox

src/meson.build

@@ -44,14 +44,10 @@ version_cpp = vcs_tag(command : version_cmd,
 
 pisp_sources += version_cpp
 
-# Label the .so with x.y versioning from the project.
-v = meson.project_version().split('.')
-soversion = v[0] + '.' + v[1]
-
 libpisp = library(
     meson.project_name(),
     pisp_sources,
-    soversion : soversion,
+    soversion : meson.project_version(),
     include_directories : include_directories(inc_dirs),
     name_prefix : '',
     install : true,