change(openvpn): default upgraded from 2.5 to 2.6

Dockerfile

@@ -85,7 +85,7 @@ ENV VPN_SERVICE_PROVIDER=pia \
     OPENVPN_PASSWORD= \
     OPENVPN_USER_SECRETFILE=/run/secrets/openvpn_user \
     OPENVPN_PASSWORD_SECRETFILE=/run/secrets/openvpn_password \
-    OPENVPN_VERSION=2.5 \
+    OPENVPN_VERSION=2.6 \
     OPENVPN_VERBOSITY=1 \
     OPENVPN_FLAGS= \
     OPENVPN_CIPHERS= \

internal/configuration/settings/openvpn.go

@@ -286,7 +286,7 @@ func (o *OpenVPN) overrideWith(other OpenVPN) {
 }
 
 func (o *OpenVPN) setDefaults(vpnProvider string) {
-	o.Version = gosettings.DefaultComparable(o.Version, openvpn.Openvpn25)
+	o.Version = gosettings.DefaultComparable(o.Version, openvpn.Openvpn26)
 	o.User = gosettings.DefaultPointer(o.User, "")
 	if vpnProvider == providers.Mullvad {
 		o.Password = gosettings.DefaultPointer(o.Password, "m")

internal/configuration/settings/settings.go

@@ -155,7 +155,7 @@ func (s Settings) Warnings() (warnings []string) {
 
 	if helpers.IsOneOf(s.VPN.Provider.Name, providers.SlickVPN) &&
 		s.VPN.Type == vpn.OpenVPN {
-		warnings = append(warnings, "OpenVPN 2.5 uses OpenSSL 3 "+
+		warnings = append(warnings, "OpenVPN 2.5 and 2.6 use OpenSSL 3 "+
 			"which prohibits the usage of weak security in today's standards. "+
 			s.VPN.Provider.Name+" uses weak security which is out "+
 			"of Gluetun's control so the only workaround is to allow such weaknesses "+

internal/configuration/settings/settings_test.go

@@ -30,7 +30,7 @@ func Test_Settings_String(t *testing.T) {
 |   |           ├── Protocol: UDP
 |   |           └── Private Internet Access encryption preset: strong
 |   └── OpenVPN settings:
-|       ├── OpenVPN version: 2.5
+|       ├── OpenVPN version: 2.6
 |       ├── User: [not set]
 |       ├── Password: [not set]
 |       ├── Private Internet Access encryption preset: strong