Add bullet about updating Positron

Author: DavisVaughan

CONTRIBUTING.md

@@ -40,6 +40,8 @@ When you want to cut a release of the Air binary and Air VS Code / OpenVSX exten
 
     -   It runs on `workflow_dispatch`, and automatically pulls in the latest release binary of Air from the binary release workflow above. It will release to both the VS Code marketplace and the OpenVSX marketplace.
 
+-   Bump the version of Air recorded in Positron's [`product.json`](https://github.com/posit-dev/positron/blob/main/product.json).
+
 -   Merge the release branch
 
     -   There is no need to bump to an intermediate "dev version" after a release.
@@ -133,4 +135,4 @@ Install the nextest cli tool using a [prebuilt binary](https://nexte.st/docs/ins
 
 Run tests locally with `just test`, which calls `cargo nextest run`. Run insta snapshot tests in "update" mode with `just test-insta`.
 
-On CI we use the nextest profile found in `.config/nextest.toml`.
+On CI we use the nextest profile found in `.config/nextest.toml`.