release/v1.15: set min go version to min upstream supported go1.16 (go-gitea#16710)

* release/v1.15: set min go version to min upstream supported 1.16

* update drone

Author: techknowlogick

.drone.yml

@@ -84,7 +84,7 @@ steps:
 
   - name: build-backend-no-gcc
     pull: always
-    image: golang:1.15 # this step is kept as the lowest version of golang that we support
+    image: golang:1.16 # this step is kept as the lowest version of golang that we support
     environment:
       GO111MODULE: on
       GOPROXY: off

Makefile

@@ -25,7 +25,7 @@ HAS_GO = $(shell hash $(GO) > /dev/null 2>&1 && echo "GO" || echo "NOGO" )
 COMMA := ,
 
 XGO_VERSION := go-1.16.x
-MIN_GO_VERSION := 001015000
+MIN_GO_VERSION := 001016000
 MIN_NODE_VERSION := 012017000
 
 DOCKER_IMAGE ?= gitea/gitea
@@ -200,7 +200,7 @@ help:
 go-check:
 	$(eval GO_VERSION := $(shell printf "%03d%03d%03d" $(shell $(GO) version | grep -Eo '[0-9]+\.[0-9.]+' | tr '.' ' ');))
 	@if [ "$(GO_VERSION)" -lt "$(MIN_GO_VERSION)" ]; then \
-		echo "Gitea requires Go 1.15 or greater to build. You can get it at https://golang.org/dl/"; \
+		echo "Gitea requires Go 1.16 or greater to build. You can get it at https://golang.org/dl/"; \
 		exit 1; \
 	fi
 

docs/config.yaml

@@ -19,7 +19,7 @@ params:
   author: The Gitea Authors
   website: https://docs.gitea.io
   version: 1.14.6
-  minGoVersion: 1.15
+  minGoVersion: 1.16
   goVersion: 1.16
   minNodeVersion: 12.17