Certificate not trusted when deploying via Docker

Error message below when wget shinyproxy in Docker deployment.

Current workaround is to manually download file and do a COPY into image.

It’d be ideal to have this automated by having a trusted certificate.

Step 3/6 : RUN wget https://www.shinyproxy.io/downloads/shinyproxy-2.1.0.jar -O /opt/shinyproxy/shinyproxy.jar
 ---> Running in d2fe57825c42
--2019-11-20 14:16:32--  https://www.shinyproxy.io/downloads/shinyproxy-2.1.0.jar
Resolving www.shinyproxy.io (www.shinyproxy.io)... 149.5.16.184
Connecting to www.shinyproxy.io (www.shinyproxy.io)|149.5.16.184|:443... connected.
ERROR: The certificate of ‘www.shinyproxy.io’ is not trusted.
ERROR: The certificate of ‘www.shinyproxy.io’ hasn't got a known issuer.