Fix CI for nim devel & 1.6

[Menduist]

No description provided.

[codecov]

Codecov Report

Merging #848 (642dd2f) into unstable (489c115) will increase coverage by 0.03%.
The diff coverage is n/a.

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable     #848      +/-   ##
============================================
+ Coverage     83.71%   83.75%   +0.03%     
============================================
  Files            85       85              
  Lines         15023    15023              
============================================
+ Hits          12576    12582       +6     
+ Misses         2447     2441       -6     

Impacted Files	Coverage Δ
libp2p/multicodec.nim	91.30% <0.00%> (-8.70%)	⬇️
libp2p/transports/wstransport.nim	85.26% <0.00%> (ø)
libp2p/muxers/mplex/mplex.nim	88.52% <0.00%> (+0.81%)	⬆️
libp2p/protocols/pubsub/pubsub.nim	82.81% <0.00%> (+1.03%)	⬆️
libp2p/protocols/secure/secure.nim	75.00% <0.00%> (+3.84%)	⬆️