[DOC, MAINT] Updated dependency version numbers

[handwerkerd]

Closes #761 .

Changes proposed in this pull request:

• Updates minimum version requirements for python dependencies in tedana/info.py to match nilearn>=0.7
• Removes minimum version requirements from docs/installation.rst & README.md so those will only need to be updated in one place

[codecov]

Codecov Report

Merging #763 (f4b4319) into main (cc7fc8f) will increase coverage by 0.18%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #763      +/-   ##
==========================================
+ Coverage   92.93%   93.11%   +0.18%     
==========================================
  Files          27       27              
  Lines        2208     2208              
==========================================
+ Hits         2052     2056       +4     
+ Misses        156      152       -4     

Impacted Files	Coverage Δ
tedana/decomposition/ica.py	96.55% <0.00%> (+13.79%)	⬆️

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[eurunuela]

LGTM!

[tsalo]

Looks great. Thanks!