Remove support for go 1.19 and 1.20, and add support for 1.23 (#1837)

.github/workflows/test.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go-version: [1.19.x, 1.20.x, 1.21.x, 1.22.x]
+        go-version: [1.21.x, 1.22.x, 1.23.x]
         os: [ubuntu-latest, macos-latest, windows-latest, macos-14]
     runs-on: ${{ matrix.os }}
     steps:

README.md

@@ -600,7 +600,7 @@ This is an **unsafe** way, the result string and `[]byte` buffer share the same
 
 * *Which GO versions are supported by fasthttp?*
 
-  Go 1.18.x. Older versions won't be supported.
+  Go 1.21.x and newer. Older versions might work, but won't officially be supported.
 
 * *Please provide real benchmark data and server information*