fix: default linux binary in installer, add context

Closes coop-cloud/organising#184

scripts/installer/installer

@@ -38,7 +38,7 @@ function install_abra_release {
   release_url=$(curl -s "$ABRA_RELEASE_URL" |
     python3 -c "import sys, json; \
                 payload = json.load(sys.stdin); \
-                url = [a['browser_download_url'] for a in payload['assets'] if 'x86_64' in a['name']][0]; \
+                url = [a['browser_download_url'] for a in payload['assets'] if 'linux_x86_64' in a['name']][0]; \
                 print(url)")
 
   echo "downloading $ABRA_VERSION x86_64 binary release for abra..."