Make `update_julia(1.1)` install 1.1, not 1.1x (e.g. 1.10)

[LilithHafner]

This predates the release of 1.9 so it's a bit early but tests are sensitive enough to start detecting this failure now that nightly is 1.10-DEV

[codecov-commenter]

Codecov Report

Merging #21 (f6064ec) into main (fd39a08) will increase coverage by 0.31%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #21      +/-   ##
==========================================
+ Coverage   86.98%   87.30%   +0.31%     
==========================================
  Files           1        1              
  Lines         169      189      +20     
==========================================
+ Hits          147      165      +18     
- Misses         22       24       +2     

Impacted Files	Coverage Δ
src/UpdateJulia.jl	87.30% <100.00%> (+0.31%)	:arrow_up:

:mega: We’re building smart automated test selection to slash your CI/CD build times. Learn more