fix bool branch interpretation

[aminnj]

We needed a specialized case to interpret boolean branches as Vector{Bool} instead of BitVector. I factored out the solution and unit test from #95 .

before

💥🚗

after

julia> using UnROOT

julia> f = UnROOT.samplefile("NanoAODv5_sample.root");

julia> f["Events/L1_ZeroBias"]
1000-element LazyBranch{Bool, UnROOT.Nojagg, Vector{Bool}}:
 1
 1
 1
 1
 1
 1
 1
 ⋮
 1
 1
 1
 1
 1
 1
 1

[codecov]

Codecov Report

Merging #102 (a282676) into master (4c2c991) will increase coverage by 0.01%.
The diff coverage is 100.00%.

❗ Current head a282676 differs from pull request most recent head 773cb42. Consider uploading reports for the commit 773cb42 to get more accurate results

@@            Coverage Diff             @@
##           master     #102      +/-   ##
==========================================
+ Coverage   88.17%   88.19%   +0.01%     
==========================================
  Files          11       11              
  Lines        1328     1330       +2     
==========================================
+ Hits         1171     1173       +2     
  Misses        157      157              

Impacted Files	Coverage Δ
src/root.jl	90.99% <100.00%> (+0.08%)	⬆️

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