Grab the first access token URL

Signed-off-by: Shalier Xia <shalierxia@microsoft.com>

.github/workflows/automerge.yml

@@ -29,7 +29,7 @@ jobs:
         payload=$(echo '{"iss": '"$ID"',"iat": '$issueTime' ,"exp": '$expireTime'}'| jq -r '(. | @base64)'| sed s/\+/-/ | sed -E s/=+$//)
         echo "$PK" > key.pem
         signature=$(echo -n "$header.$payload" | openssl dgst -sha256 -binary -sign key.pem | openssl enc -base64 | tr -d '\n=' | tr -- '+/' '-_')
-        tokenURL=$(curl -i -s -X GET -H "Authorization: Bearer $header.$payload.$signature" -H "Accept: application/vnd.github.v3+json" https://api.github.com/app/installations | grep 'access_tokens_url' | awk '{print $2}' | sed -e 's/^"//' -e 's/",$//')
+        tokenURL=$(curl -i -s -X GET -H "Authorization: Bearer $header.$payload.$signature" -H "Accept: application/vnd.github.v3+json" https://api.github.com/app/installations | grep -m1 'access_tokens_url' | awk '{print $2}' | sed -e 's/^"//' -e 's/",$//')
         token=$(curl -i -s -X POST -H "Authorization: Bearer $header.$payload.$signature" -H "Accept: application/vnd.github.v3+json" "$tokenURL" | grep 'token'| awk '{print $2}' | sed -e 's/^"//' -e 's/",$//')
         echo "GITHUB_TOKEN=$token" >> "$GITHUB_ENV"
     - name: automerge