Specify 'tool-sync' asset name more precisely (#105)

This is needed because in the new release we also generate SHA256 sums
and those assets could be found before the actual archive. So I specify
the asset name more precisely.

I guess we need #50 to address this problem gracefully 😮‍💨 

### Additional tasks

- [ ] Documentation for changes provided/changed
- [ ] Tests added

src/sync/db.rs

@@ -89,9 +89,9 @@ pub fn build_db() -> BTreeMap<String, ToolInfo> {
             repo: "tool-sync".to_string(),
             exe_name: "tool".to_string(),
             asset_name: AssetName {
-                linux: Some("x86_64-unknown-linux-gnu".to_string()),
-                macos: Some("x86_64-apple-darwin".to_string()),
-                windows: Some("x86_64-pc-windows-msvc".to_string()),
+                linux: Some("x86_64-unknown-linux-gnu.tar.gz".to_string()),
+                macos: Some("x86_64-apple-darwin.tar.gz".to_string()),
+                windows: Some("x86_64-pc-windows-msvc.zip".to_string()),
             },
             tag: ToolInfoTag::Latest,
         },