docs: Add proto v0.28 blog post. (#1275)

Add blog post.

website/blog/2024-01-17_proto-v0.28.mdx

@@ -0,0 +1,33 @@
+---
+slug: proto-v0.28
+title: proto v0.28 - Upgraded WASM runtime
+authors: [milesj]
+tags: [proto, wasm, runtime, extism]
+# image: ./img/proto/v0.26.png
+---
+
+This is a small release that primarily upgrades our WASM runtime.
+
+<!--truncate-->
+
+## Upgraded WASM runtime
+
+proto utilizes [Extism](https://extism.org/) for our WASM plugin architecture, which internally uses
+[wasmtime](https://wasmtime.dev/) as our execution runtime. Up until this point, we've been using a
+beta release of Extism, v0.5, which has worked quite nicely. We've also been working closely with
+the Extism team to report bugs, provide feedback, and help improve the project. Once such feature
+was the massive performance gains in [proto v0.24](./proto-v0.24).
+
+Thanks to all the hard work from the Extism team over the past year, an official v1.0 was released.
+Because this was a major release, it did include breaking changes around the WASM runtime, and as
+such, proto WASM plugins before v0.28 are _no longer compatible_, and will need to be recompiled
+with the latest PDKs. Our proto TOML plugins are not affected.
+
+## Other changes
+
+View the [official release](https://github.com/moonrepo/proto/releases/tag/v0.28.0) for a full list
+of changes.
+
+- Will now display an upgrade message when the current proto version is out of date.
+- Improved error messages to include plugin specific information.
+- Updated our "last used at" logic to avoid race conditions with the tool manifest.

website/docs/proto/wasm-plugin.mdx

@@ -92,12 +92,16 @@ provide a mechanism known as host functions, which are functions that are implem
 
 - [`exec_command`](https://docs.rs/proto_pdk/latest/proto_pdk/macro.exec_command.html) - Execute a
   system command on the host machine, with a provided list of arguments or environment variables.
+- [`from_virtual_path`](https://docs.rs/proto_pdk/latest/proto_pdk/macro.real_path.html) - Converts
+  a virtual path into a real path.
 - [`get_env_var`](https://docs.rs/proto_pdk/latest/proto_pdk/macro.host_env.html) - Get an
   environment variable value from the host environment.
 - [`host_log`](https://docs.rs/proto_pdk/latest/proto_pdk/macro.host_log.html) - Log a message to
   the host's stderr. This acts like tracing logs, and is not a general purpose stdout logger.
 - [`set_env_var`](https://docs.rs/proto_pdk/latest/proto_pdk/macro.host_env.html) - Set an
   environment variable to the host environment.
+- [`to_virtual_path`](https://docs.rs/proto_pdk/latest/proto_pdk/macro.virtual_path.html) - Converts
+  a real path into a virtual path.
 
 To use host functions, you'll need to make them available by registering them at the top of your
 Rust file (only add the functions you want to use).
@@ -106,9 +110,11 @@ Rust file (only add the functions you want to use).
 #[host_fn]
 extern "ExtismHost" {
     fn exec_command(input: Json<ExecCommandInput>) -> Json<ExecCommandOutput>;
-    fn get_env_var(key: &str) -> String;
+    fn from_virtual_path(path: String) -> String;
+    fn get_env_var(key: String) -> String;
     fn host_log(input: Json<HostLogInput>);
-    fn set_env_var(key: &str, value: &str);
+    fn set_env_var(key: String, value: String);
+    fn to_virtual_path(path: String) -> String;
 }
 ```
 
@@ -118,6 +124,9 @@ extern "ExtismHost" {
 // Set a value
 host_env!("ENV_VAR", "value");
 
+// Append to path
+host_env!("PATH", "/userhome/some/virtual/path");
+
 // Get a value (returns an `Option`)
 let value = host_env!("ENV_VAR");
 ```
@@ -136,8 +145,7 @@ exec_command!(inherit, "npm", ["install"]);
 exec_command!(ExecCommandInput {
     command: "npm".into(),
     args: vec!["install".into()],
-    env_vars: HashMap::new(),
-    stream: false,
+    ..ExecCommandInput::default()
 });
 ```