Change versioning scheme.

Author: alexrp

README.md

@@ -10,4 +10,5 @@ used by other projects.
   `linux-arm64`, `osx-x64`, `win-x86`, etc.
 * Only the RIDs that are relevant to the .NET ecosystem will be covered (so e.g.
   `Zig.Toolset.linux-riscv64` will not be available).
-* The package version will match the official Zig release's version.
+* The package version will match the official Zig release's version, with an
+  extra fourth component added indicating the packaging version.

RELEASE.md

@@ -3,9 +3,10 @@
 When a new Zig version is released, the process is as follows:
 
 * Update the `Version` property in
-  [`Directory.Build.props`](Directory.Build.props).
+  [`Directory.Build.props`](Directory.Build.props). Reset the fourth component
+  to zero.
 * Commit the change.
-* Tag a release as e.g. `v0.8.0`.
+* Tag a release as e.g. `v0.8.0.0`.
 * Push the commit and the tag.
 * Edit the draft release on GitHub to add a release note link, such as
   [this one](https://ziglang.org/download/0.8.0/release-notes.html).