switch min version of go to 1.15 (#3211)

.github/workflows/gin.yml

@@ -28,7 +28,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        go: [1.14, 1.15, 1.16, 1.17, 1.18]
+        go: [1.15, 1.16, 1.17, 1.18]
         test-tags: ['', nomsgpack]
         include:
           - os: ubuntu-latest

README.md

@@ -86,7 +86,7 @@ Gin is a web framework written in Go (Golang). It features a martini-like API wi
 
 To install Gin package, you need to install Go and set your Go workspace first.
 
-1. You first need [Go](https://golang.org/) installed (**version 1.14+ is required**), then you can use the below Go command to install Gin.
+1. You first need [Go](https://golang.org/) installed (**version 1.15+ is required**), then you can use the below Go command to install Gin.
 
 ```sh
 $ go get -u github.com/gin-gonic/gin

debug.go

@@ -67,7 +67,7 @@ func getMinVer(v string) (uint64, error) {
 
 func debugPrintWARNINGDefault() {
 	if v, e := getMinVer(runtime.Version()); e == nil && v <= ginSupportMinGoVer {
-		debugPrint(`[WARNING] Now Gin requires Go 1.14+.
+		debugPrint(`[WARNING] Now Gin requires Go 1.15+.
 
 `)
 	}

debug_test.go

@@ -104,7 +104,7 @@ func TestDebugPrintWARNINGDefault(t *testing.T) {
 	})
 	m, e := getMinVer(runtime.Version())
 	if e == nil && m <= ginSupportMinGoVer {
-		assert.Equal(t, "[GIN-debug] [WARNING] Now Gin requires Go 1.14+.\n\n[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.\n\n", re)
+		assert.Equal(t, "[GIN-debug] [WARNING] Now Gin requires Go 1.15+.\n\n[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.\n\n", re)
 	} else {
 		assert.Equal(t, "[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.\n\n", re)
 	}