meson: make version numbers ints and fix int/string comparison

WARNING: Trying to compare values of different types (str, int).
The result of this is undefined and will become a hard error
in a future Meson release.
diff --git a/meson.build b/meson.build
index 642b60c..8855171 100644
--- a/meson.build
+++ b/meson.build
@@ -6,9 +6,9 @@
 
 gst_version = meson.project_version()
 version_arr = gst_version.split('.')
-gst_version_major = version_arr[0]
-gst_version_minor = version_arr[1]
-gst_version_micro = version_arr[2]
+gst_version_major = version_arr[0].to_int()
+gst_version_minor = version_arr[1].to_int()
+gst_version_micro = version_arr[2].to_int()
 if version_arr.length() == 4
   gst_version_nano = version_arr[3].to_int()
 else
@@ -21,7 +21,7 @@
 soversion = 0
 # maintaining compatibility with the previous libtool versioning
 # current = minor * 100 + micro
-libversion = '@0@.@1@.0'.format(soversion, gst_version_minor.to_int() * 100 + gst_version_micro.to_int())
+libversion = '@0@.@1@.0'.format(soversion, gst_version_minor * 100 + gst_version_micro)
 
 prefix = get_option('prefix')
 libtype = get_option('library_format')