Merge #5216

5216: Add support for GITHUB_TOKEN authentication in installation script r=curquiza a=Sherlouk

# Pull Request

## What does this PR do?
This tweaks the install script to support detection of a "GITHUB_TOKEN" variable. This is well documented [here](https://docs.github.com/en/actions/security-for-github-actions/security-guides/automatic-token-authentication) but is useful for GitHub Actions workflows, reducing the need for users to maintain a separate PAT token. This should be more reliable.

Note: these changes have been tested on the Swift project: https://github.com/meilisearch/meilisearch-swift/pull/464.

## PR checklist
Please check if your PR fulfills the following requirements:
- [x] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
- [x] Have you read the contributing guidelines?
- [x] Have you made sure that the title is accurate and descriptive of the changes?

Thank you so much for contributing to Meilisearch!


Co-authored-by: James Sherlock <15193942+Sherlouk@users.noreply.github.com>

download-latest.sh

@@ -33,10 +33,12 @@ get_latest() {
         exit 1
     fi
 
-    if [ -z "$GITHUB_PAT" ]; then
-        curl -s "$latest_release" > "$temp_file" || return 1
-    else
+    if [ -n "$GITHUB_TOKEN" ]; then
+        curl -H "Authorization: Bearer $GITHUB_TOKEN" -s "$latest_release" > "$temp_file" || return 1
+    elif [ -n "$GITHUB_PAT" ]; then
         curl -H "Authorization: token $GITHUB_PAT" -s "$latest_release" > "$temp_file" || return 1
+    else
+        curl -s "$latest_release" > "$temp_file" || return 1
     fi
 
     latest="$(cat "$temp_file" | grep '"tag_name":' | cut -d ':' -f2 | tr -d '"' | tr -d ',' | tr -d ' ')"