require go 1.19, test with 1.20 too (#1935)

.github/workflows/go-tests.yml

@@ -36,7 +36,7 @@ jobs:
   build:
     strategy:
       matrix:
-        go-version: [1.18, 1.x]
+        go-version: ["1.19", "1.20.0-rc.1"]
 
     name: "Build + tests"
     runs-on: ubuntu-latest

Makefile

@@ -45,7 +45,7 @@ CSCLI_BIN = cscli$(EXT)
 BUILD_CMD = build
 
 MINIMUM_SUPPORTED_GO_MAJOR_VERSION = 1
-MINIMUM_SUPPORTED_GO_MINOR_VERSION = 18
+MINIMUM_SUPPORTED_GO_MINOR_VERSION = 19
 
 go_major_minor = $(subst ., ,$(BUILD_GOVERSION))
 GO_MAJOR_VERSION = $(word 1, $(go_major_minor))