v1.9: update version numbers

Update the library's (API) version number to v1.9.0. Also update the
soname version number to 2.0, since we've had breaking ABI changes
to the library.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "libgit2",
-  "version": "1.8.2",
+  "version": "1.9.0",
   "repo": "https://github.com/libgit2/libgit2",
   "description": " A cross-platform, linkable library implementation of Git that you can use in your application.",
   "install": "mkdir build && cd build && cmake .. && cmake --build ."