chore: prysm - set stable image as default (#793)

Author: barnabasbusa

src/package_io/input_parser.star

@@ -20,7 +20,7 @@ DEFAULT_CL_IMAGES = {
     "lighthouse": "ethpandaops/lighthouse:stable",
     "teku": "consensys/teku:latest",
     "nimbus": "statusim/nimbus-eth2:multiarch-latest",
-    "prysm": "gcr.io/prysmaticlabs/prysm/beacon-chain:latest",
+    "prysm": "gcr.io/prysmaticlabs/prysm/beacon-chain:stable",
     "lodestar": "chainsafe/lodestar:latest",
     "grandine": "sifrai/grandine:stable",
 }
@@ -38,7 +38,7 @@ DEFAULT_VC_IMAGES = {
     "lighthouse": "ethpandaops/lighthouse:stable",
     "lodestar": "chainsafe/lodestar:latest",
     "nimbus": "statusim/nimbus-validator-client:multiarch-latest",
-    "prysm": "gcr.io/prysmaticlabs/prysm/validator:latest",
+    "prysm": "gcr.io/prysmaticlabs/prysm/validator:stable",
     "teku": "consensys/teku:latest",
     "grandine": "sifrai/grandine:stable",
 }