add reference for zkDCAP image ID

Signed-off-by: Jun Kimura <jun.kimura@datachain.jp>

Author: bluele

tests/e2e/scripts/run_e2e_test.sh

@@ -10,6 +10,7 @@ export NO_RUN_LCP=false
 export LCP_ENCLAVE_DEBUG=0
 export LCP_KEY_EXPIRATION=86400
 # LCP_RISC0_IMAGE_ID must be set to the same value as in the LCP service
+# e.g. https://github.com/datachainlab/zkdcap/blob/fd44cfc9718a0bd4a58f5dbf2b0b89c25144893d/zkvm/risc0/src/methods.rs#L3
 LCP_RISC0_IMAGE_ID=${LCP_RISC0_IMAGE_ID:-0xe5056aa7a8064abeb648b31d5efa8697a79d416b937cb917d1428cec91a56c67}
 export ZKDCAP=false
 export LCP_ZKDCAP_RISC0_MOCK=false