docs: update readme for v0.7.1

Author: openoms

README.md

@@ -58,9 +58,8 @@ A minimalistic, security focused linux environment for JoinMarket with a termina
 **JoininBox operates on the minimum viable hardware under the assumption that the seed (and passphrase) of the wallets used is safely backed up and can be used to recover the funds!**
 
 ## Set up using an SDcard image
-* Download the latest SDcard image for the Raspberry Pi 4 or 3 generated with Packer in GitHub actions
-  * Download link: <https://github.com/openoms/joininbox/suites/7702238931/artifacts/322134211>
-  * Details of the build: <https://github.com/openoms/joininbox/actions/runs/2812704764>
+* Download the zip of the latest successful SDcard image build for the Raspberry Pi 4 or 3 from
+  <https://github.com/openoms/joininbox/actions/workflows/arm64-rpi-image-build.yml>
 * unzip and check the sha256sum verifying the .gz file integrity
   ```
   sha256sum -c joininbox-arm64-rpi.img.gz.sha256