Add support for apc_modbus (#449)

Author: PaulSD

nut/DOCS.md

@@ -128,8 +128,7 @@ _Refer to the [`ups.conf(5)`][ups-conf] documentation for more information._
 
 #### Sub-option: `name`
 
-The name of the UPS. The name `default` is used internally, so you can’t use
-it in this file.
+The name of the UPS. You cannot use any space characters or the name `default`.
 
 #### Sub-option: `driver`
 

nut/Dockerfile

@@ -6,10 +6,11 @@ FROM ${BUILD_FROM}
 # hadolint ignore=DL3003
 RUN \
     apt-get update \
-    && apt-get install -y --no-install-recommends\
+    && apt-get install -y --no-install-recommends \
         nut=2.8.1-5 \
         nut-snmp=2.8.1-5 \
         nut-xml=2.8.1-5 \
+        nut-modbus=2.8.1-5 \
         usbutils=1:018-2 \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*