Plugin breaks after 50 scrapes

[jakubfaldasz]

So I noticed a weird thing when the plugin is scraping data from the server, after some time (12.5 minutes precisely - 50 scrapes in 15 seconds interval) the plugin stopped working. The read method failed and the logs were almost identical to the ones reported here. It seems that the after some time the opcua connections all got timeouts at the same time because they weren't closed correctly by the library.

I figured that updating the gopcua library might be a good idea and in fact it did fix this issue.