nbconvert is reported as a missing dependency

Issue Report Checklist

• Searched the issues page for similar reports
• Read the relevant sections of the Spyder Troubleshooting Guide and followed its advice
• Reproduced the issue after updating with conda update spyder (or pip, if not using Anaconda)
• Could not reproduce inside jupyter qtconsole (if console-related)
• Tried basic troubleshooting (if a bug/error)
  • Restarted Spyder
  • Reset preferences with spyder --reset
  • Reinstalled the latest version of Anaconda
  • Tried the other applicable steps from the Troubleshooting Guide
• Completed the Problem Description, Steps to Reproduce and Version sections below

Problem Description

When I start spyder I get a message that I have missing dependencies:

nbconvert >=4.0: None (NOK)

despite having version 5.3.1 installed (via conda)

What steps reproduce the problem?

1. conda create --name test python=3.7 && conda activate test
2. conda install spyder
3. spyder

What is the expected output? What do you see instead?

Expected output is no error.

What I see is:

Versions

• Spyder version: 3.3.3
• Python version: 3.7
• Qt version: 5.9.7-h5867ecd_1
• PyQt version: 5.9.2-py37h05f1152_2
• Operating System name/version: Ubuntu 18.04