feat: tensorflow multi outputs support

[larme]

What does this PR address?

Fixes #(issue)

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[codecov]

Codecov Report

Merging #3115 (23e8ecf) into main (364f9e5) will decrease coverage by 0.04%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #3115      +/-   ##
==========================================
- Coverage   21.48%   21.44%   -0.05%     
==========================================
  Files         102      102              
  Lines        9764     9783      +19     
  Branches     1698     1706       +8     
==========================================
  Hits         2098     2098              
- Misses       7619     7638      +19     
  Partials       47       47              

Impacted Files	Coverage Δ
src/bentoml/_internal/frameworks/tensorflow_v2.py	0.00% <0.00%> (ø)
src/bentoml/_internal/utils/tensorflow.py	0.00% <0.00%> (ø)

[aarnphm]

LGTM.