build: update CI builds to use go 1.15.7

.github/workflows/main.yml

@@ -24,7 +24,7 @@ env:
   # /dev.Dockerfile
   # /make/builder.Dockerfile
   # /.github/workflows/release.yml
-  GO_VERSION: 1.15.6
+  GO_VERSION: 1.15.7
 
 jobs:
   ########################

.github/workflows/release.yaml

@@ -16,7 +16,7 @@ env:
   # /dev.Dockerfile
   # /make/builder.Dockerfile
   # /.github/workflows/main.yml
-  GO_VERSION: 1.15.6
+  GO_VERSION: 1.15.7
 
 jobs:
   main:

.travis.yml

@@ -21,7 +21,7 @@ go:
   # /make/builder.Dockerfile
   # /.github/workflows/main.yml
   # /.github/workflows/release.yml
-  - "1.15.6"
+  - "1.15.7"
 
 env:
   global:

lnrpc/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.15.6-buster
+FROM golang:1.15.7-buster
 
 RUN apt-get update && apt-get install -y \
   git \