chore: drop go 1.15 support

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
   test:
     strategy:
       matrix:
-        go: [ '1.15.x', '1.16.x', '1.17.x', '1.18.x' ]
+        go: [ '1.16.x', '1.17.x', '1.18.x' ]
         platform: [ubuntu-latest, macos-latest]
     runs-on: ${{ matrix.platform }}
     steps:

README.md

@@ -52,12 +52,9 @@ Swag converts Go annotations to Swagger Documentation 2.0. We've created a varie
 
 2. Download swag by using:
 ```sh
-$ go get -u github.com/swaggo/swag/cmd/swag
-
-# 1.16 or newer
 $ go install github.com/swaggo/swag/cmd/swag@latest
 ```
-To build from source you need [Go](https://golang.org/dl/) (1.15 or newer).
+To build from source you need [Go](https://golang.org/dl/) (1.16 or newer).
 
 Or download a pre-compiled binary from the [release page](https://github.com/swaggo/swag/releases).
 

README_zh-CN.md

@@ -47,13 +47,10 @@ Swag将Go的注释转换为Swagger2.0文档。我们为流行的 [Go Web Framewo
 2. 使用如下命令下载swag：
 
 ```bash
-$ go get -u github.com/swaggo/swag/cmd/swag
-
-# 1.16 及以上版本
 $ go install github.com/swaggo/swag/cmd/swag@latest
 ```
 
-从源码开始构建的话，需要有Go环境（1.15及以上版本）。
+从源码开始构建的话，需要有Go环境（1.16及以上版本）。
 
 或者从github的release页面下载预编译好的二进制文件。