[chore] update viper version (#2539)

* update viper version

* removes our last uses of the slice package

* fix tests

vendor/github.com/spf13/viper/file.go

@@ -0,0 +1,56 @@
+//go:build !finder
+
+package viper
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/spf13/afero"
+)
+
+// Search all configPaths for any config file.
+// Returns the first path that exists (and is a config file).
+func (v *Viper) findConfigFile() (string, error) {
+	v.logger.Info("searching for config in paths", "paths", v.configPaths)
+
+	for _, cp := range v.configPaths {
+		file := v.searchInPath(cp)
+		if file != "" {
+			return file, nil
+		}
+	}
+	return "", ConfigFileNotFoundError{v.configName, fmt.Sprintf("%s", v.configPaths)}
+}
+
+func (v *Viper) searchInPath(in string) (filename string) {
+	v.logger.Debug("searching for config in path", "path", in)
+	for _, ext := range SupportedExts {
+		v.logger.Debug("checking if file exists", "file", filepath.Join(in, v.configName+"."+ext))
+		if b, _ := exists(v.fs, filepath.Join(in, v.configName+"."+ext)); b {
+			v.logger.Debug("found file", "file", filepath.Join(in, v.configName+"."+ext))
+			return filepath.Join(in, v.configName+"."+ext)
+		}
+	}
+
+	if v.configType != "" {
+		if b, _ := exists(v.fs, filepath.Join(in, v.configName)); b {
+			return filepath.Join(in, v.configName)
+		}
+	}
+
+	return ""
+}
+
+// exists checks if file exists.
+func exists(fs afero.Fs, path string) (bool, error) {
+	stat, err := fs.Stat(path)
+	if err == nil {
+		return !stat.IsDir(), nil
+	}
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	return false, err
+}