CI(scripts): pin geth to v1.10.26 (#5900)

Declared GETH version in one location per bash script. 

This will make pinning and unpinning GETH easier.

scripts/ci.sh

@@ -1,5 +1,13 @@
 #!/usr/bin/env bash
 
+# Set geth version to stable, or pin to a specific version
+# as necessary when geth release breaks CI
+# Snoop these 
+# - https://hub.docker.com/r/ethereum/client-go
+# - https://github.com/ethereum/go-ethereum/releases
+# GETH_VERSION="stable"
+GETH_VERSION="v1.10.26"
+
 # Exit script as soon as a command fails.
 set -o errexit
 
@@ -11,7 +19,7 @@ run_geth() {
  -p 8545:8545 \
  -p 8546:8546 \
  -p 30303:30303 \
- ethereum/client-go:stable \
+ "ethereum/client-go:$GETH_VERSION" \
  --http \
  --http.addr '0.0.0.0' \
  --http.port 8545 \
@@ -41,7 +49,7 @@ if [ "$INTEGRATION" = true ]; then
 elif [ "$GETH" = true ]; then
 
  sudo apt install -y jq
- docker pull ethereum/client-go:v1.10.19
+ docker pull "ethereum/client-go:$GETH_VERSION"
  run_geth
  sleep 30
  lerna run --scope truffle test --stream -- --exit

scripts/geth.sh

@@ -1,6 +1,14 @@
 #!/usr/bin/env bash
 
-docker pull ethereum/client-go:stable
+# Set geth version to stable, or pin to a specific version
+# as necessary when geth release breaks CI
+# Snoop these 
+# - https://hub.docker.com/r/ethereum/client-go
+# - https://github.com/ethereum/go-ethereum/releases
+# GETH_VERSION="stable"
+GETH_VERSION="v1.10.26"
+
+docker pull "ethereum/client-go:$GETH_VERSION"
 
 CID=$(docker run \
  -v /$PWD/scripts:/scripts \
@@ -9,7 +17,7 @@ CID=$(docker run \
  -p 8545:8545 \
  -p 8546:8546 \
  -p 30303:30303 \
- ethereum/client-go:stable \
+ "ethereum/client-go:$GETH_VERSION" \
  --http \
  --http.addr '0.0.0.0' \
  --http.port 8545 \