use golang 1.15.5 version (#34)

Author: ramilexe

.github/workflows/on-master.yaml

@@ -4,6 +4,8 @@ on:
   push:
     branches:
       - statediff_at_anyblock-1.9.11
+      - v1.9.23-statediff-0.0.10
+      - v1.9.23-statediff-0.0.9
 
 jobs:
   build:

Dockerfile.amd64

@@ -1,5 +1,5 @@
 # Build Geth in a stock Go builder container
-FROM golang:1.13 as builder
+FROM golang:1.15.5 as builder
 
 #RUN apk add --no-cache make gcc musl-dev linux-headers git