Repository: nf-core/tools

Issue:
Linting: Anaconda API fails for some packages 
```
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-rmarkdown=1.10
  http://nf-co.re/errors#8: Conda dependency had an unknown version: fasttree=2.1.10
  http://nf-co.re/errors#8: Conda dependency had an unknown version: mafft=7.310
  http://nf-co.re/errors#8: Conda dependency had an unknown version: vsearch=2.7.0
  http://nf-co.re/errors#8: Conda dependency had an unknown version: bleach=2.1.3
  http://nf-co.re/errors#8: Conda dependency had an unknown version: emperor=1.0.0beta16
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-bh=1.66.0_1
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-data.table=1.11.4
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-digest=0.6.15
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-futile.logger=1.4.3
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-lambda.r=1.2
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-matrixstats=0.53.1
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-rcppparallel=4.4.0
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-scales=0.5.0
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-snow=0.4_2
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-stringr=1.3.0
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-tibble=1.4.2
  http://nf-co.re/errors#8: Conda dependency had an unknown version: r-viridislite=0.3.0
  http://nf-co.re/errors#8: Conda dependency had an unknown version: urllib3=1.23
  http://nf-co.re/errors#8: Conda dependency had an unknown version: q2-deblur=2018.6.0
```

Pinging in @sven1103 and @ewels do you guys have an idea? 



Discussion:
Could be the Anaconda API being unhappy? Can you try the URL manually?

`'https://api.anaconda.org/package/{}/{}'.format(ch, depname)`

https://github.com/nf-core/tools/blob/aa947db2782715433fe1b9216de691e942370165/nf_core/lint.py#L599
I tried, getting this:

```
https://api.anaconda.org/package/conda-forge/vsearch


error | "\"vsearch\" could not be found"
-- | --



```
Same for others:

```
{
  "error": "\"r-rmarkdown=1.10\" could not be found"
}
```
Strange - https://api.anaconda.org/package/conda-forge/r-rmarkdown works ok for me, MultiQC also works fine: https://api.anaconda.org/package/bioconda/multiqc

`vsearch` doesn't work, but I can't find it on the conda forge website either: https://conda-forge.org/feedstocks/
Yeah same for me... there are  a bunch of tools not found.... 

Resolving patch:
diff --git a/nf_core/lint.py b/nf_core/lint.py
--- a/nf_core/lint.py
+++ b/nf_core/lint.py
@@ -581,6 +581,17 @@ def check_anaconda_package(self, dep):
         # Check if each dependency is the latest available version
         depname, depver = dep.split('=', 1)
         dep_channels = self.conda_config.get('channels', [])
+        # 'defaults' isn't actually a channel name. See https://docs.anaconda.com/anaconda/user-guide/tasks/using-repositories/
+        if 'defaults' in dep_channels:
+            dep_channels.remove('defaults')
+            dep_channels.extend([
+                'main',
+                'anaconda',
+                'r',
+                'free',
+                'archive',
+                'anaconda-extras'
+            ])
         if '::' in depname:
             dep_channels = [depname.split('::')[0]]
             depname = depname.split('::')[1]


Test patch: