Avoid stopping the installation for warning messages

[wenbostar]

> BiocManager::install("wenbostar/PGA")

Bioconductor version 3.9 (BiocManager 1.30.10), R 3.6.0 (2019-04-26)
Installing github package(s) 'wenbostar/PGA'
Downloading GitHub repo wenbostar/PGA@master
√  checking for file 'C:\Users\wb\AppData\Local\Temp\Rtmp6fyOgl\remotes269073a869ae\wenbostar-PGA-98cac29/DESCRIPTION' (934ms)
-  preparing 'PGA': (601ms)
√  checking DESCRIPTION meta-information ... 
-  checking for LF line-endings in source and make files and shell scripts
-  checking for empty or unneeded directories
-  building 'PGA_1.15.1.tar.gz'
   
* installing *source* package 'PGA' ...
** using staged installation
** R
** inst
** byte-compile and prepare package for lazy loading
Error: (converted from warning) package 'IRanges' was built under R version 3.6.1
Execution halted
ERROR: lazy loading failed for package 'PGA'
* removing 'e:/R/R-3.6.0/library/PGA'
* restoring previous 'e:/R/R-3.6.0/library/PGA'
Error: Failed to install 'PGA' from GitHub:
  (converted from warning) installation of package ‘C:/Users/**/AppData/Local/Temp/***/PGA_1.15.1.tar.gz’ had non-zero exit status

[wenbostar]

## https://github.com/r-lib/remotes#environment-variables
Sys.setenv(R_REMOTES_NO_ERRORS_FROM_WARNINGS="true")
BiocManager::install("wenbostar/PGA")