update minimum go version to go1.17

Versions of go below go1.18 have reached EOL, but some projects
may be slightly behind and still on go1.17.

This patch updates the minimum Go version to go1.17, as older versions
are broken in CI:

    Error: ../../../go/pkg/mod/github.com/kyoh86/richgo@v0.3.11/config/load.go:64:9: undefined: os.ReadFile
    note: module requires Go 1.17
    Error: Process completed with exit code 2.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

.github/workflows/test.yml

@@ -63,8 +63,6 @@ jobs:
         - ubuntu
         - macOS
         go:
-        - 15
-        - 16
         - 17
         - 18
         - 19
@@ -81,12 +79,8 @@ jobs:
 
     - run: |
         export GOBIN=$HOME/go/bin
-        case "${{ matrix.go }}" in
+        go install github.com/kyoh86/richgo@latest
-          14|15) _version='';;
+        go install github.com/mitchellh/gox@latest
-          *) _version='@latest';;
-        esac
-        go install github.com/kyoh86/richgo"${_version}"
-        go install github.com/mitchellh/gox"${_version}"
 
     - run: RICHGO_FORCE_COLOR=1 PATH=$HOME/go/bin/:$PATH make richtest
 

go.mod

@@ -1,6 +1,6 @@
 module github.com/spf13/cobra
 
-go 1.15
+go 1.17
 
 require (
 	github.com/cpuguy83/go-md2man/v2 v2.0.2
@@ -8,3 +8,5 @@ require (
 	github.com/spf13/pflag v1.0.5
 	gopkg.in/yaml.v3 v3.0.1
 )
+
+require github.com/russross/blackfriday/v2 v2.1.0 // indirect