libosmocore: Update LIBVERSION because of ABI chaanges

The recent convolutional code changes break the ABI.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/src/Makefile.am b/src/Makefile.am
index 25da356..079d0b4 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -2,7 +2,7 @@
 
 # This is _NOT_ the library release version, it's an API version.
 # Please read Chapter 6 "Library interface versions" of the libtool documentation before making any modification
-LIBVERSION=3:0:0
+LIBVERSION=4:0:0
 
 INCLUDES = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)/include
 AM_CFLAGS = -fPIC -Wall