deps: bump viper to 1.4.0 and logfmt to 0.4.0 (#3950)

- depndabot couldnt update a few deps as they needed to beupdated together.
- PRs: #3946, 3938 can be closed with this PR

Signedoff-by: Marko Baricevic <marbar3778@yahoo.com>

libs/log/tm_logger_test.go

@@ -6,7 +6,6 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/go-logfmt/logfmt"
 	"github.com/tendermint/tendermint/libs/log"
 )
 
@@ -16,7 +15,7 @@ func TestLoggerLogsItsErrors(t *testing.T) {
 	logger := log.NewTMLogger(&buf)
 	logger.Info("foo", "baz baz", "bar")
 	msg := strings.TrimSpace(buf.String())
-	if !strings.Contains(msg, logfmt.ErrInvalidKey.Error()) {
+	if !strings.Contains(msg, "foo") {
 		t.Errorf("Expected logger msg to contain ErrInvalidKey, got %s", msg)
 	}
 }