Make your CIPD package visible to Fuchsia developers

After uploading a prebuilt package to CIPD, to make it available to Fuchsia developers, you need to update a Jiri manifest listed under ${FUCHSIA_DIR}/integration/.

Do the following:

Locate the manifest file in ${FUCHSIA_DIR}/integration/.
Determine the Jiri checkout path. This should be under ${FUCHSIA_DIR}/prebuilt/ with a path reflecting the CIPD one.

For example, ${FUCHSIA_DIR}/prebuilt/third_party/ninja/linux-x64/ is used for the package at CIPD path fuchsia/third_party/ninja/linux-amd64 (notice that they use different conventions for the CPU architecture).
Add or update the Jiri manifest entry appropriately (see other existing entries for examples).

For instance, the following entry is for the QEMU emulator binary:
```
<package name="fuchsia/third_party/qemu/${platform}"
         version="git_revision:533bf2563d0213a7e002d9fcde75519d30ffa70f,1"
         platforms="linux-amd64,linux-arm64,mac-amd64"
         path="prebuilt/third_party/qemu/{{.OS}}-{{.Arch}}"/>
```
Notice the following in the example above:
- The name attribute points to the CIPD package path where ${platform} expands to a string matching the CIPD-compatible host platform name (for example, linux-amd64).
- The version attribute points to a CIPD tag for the package's revision to download.
- The path attribute points to the checkout path under ${FUCHSIA_DIR}. This attribute uses a special pattern that expands to a Fuchsia-compatible system and CPU architecture names for developers or infrastructure bot machines (for example, linux-x64).
- The platforms attribute is optional and restricts the list of supported build platforms (Jiri doesn't download this specific package on unlisted systems).
If necessary, update the Jiri lock files for the Fuchsia project.
Create a new branch under integration (or whatever directory contains your Jiri manifest for prebuilts) that includes your manifest change (and jiri.lock changes if required) and upload it to Gerrit for review.