specify timezone to so build occurs after MRAN makes snapshot

Makefile

@@ -5,7 +5,7 @@ r-ver: .PHONY
 rstudio: .PHONY 
 	docker build --build-arg RSTUDIO_VERSION=1.0.44 -t rocker/rstudio:${R_VERSION} rstudio/${R_VERSION}
 tidyverse: .PHONY 
-	docker build --build-arg BUILD_DATE=$(date -I) -t rocker/tidyverse:${R_VERSION} tidyverse/${R_VERSION}
+	docker build --build-arg BUILD_DATE=$(date -I --date='TZ="America/Los_Angeles"') -t rocker/tidyverse:${R_VERSION} tidyverse/${R_VERSION}
 verse: .PHONY 
 	docker build -t rocker/verse:${R_VERSION} verse/${R_VERSION}
 

tidyverse/3.3.2/Dockerfile

@@ -8,7 +8,7 @@ RUN apt-get update -qq && apt-get -y --no-install-recommends install \
   libmariadb-client-lgpl-dev \
   libpq-dev \
   ## Set default repo to install all packages from date-locked MRAN snapshot of CRAN
-  && [ -z "$BUILD_DATE" ] && BUILD_DATE=$(date -I) || true \
+  && [ -z "$BUILD_DATE" ] && BUILD_DATE=$(date -I --date='TZ="America/Los_Angeles"') || true \
   && MRAN=https://mran.microsoft.com/snapshot/$BUILD_DATE \
   && echo "options(repos = c(CRAN = 'https://cran.rstudio.com', MRAN = '$MRAN'))" > /usr/local/lib/R/etc/Rprofile.site \
   && Rscript -e "install.packages(c('RSQLite', 'RMySQL', 'RPostgreSQL'), repo = getOption('repos')[['MRAN']])" \

tidyverse/Dockerfile

@@ -8,7 +8,7 @@ RUN apt-get update -qq && apt-get -y --no-install-recommends install \
   libmariadb-client-lgpl-dev \
   libpq-dev \
   ## Set default repo to install all packages from date-locked MRAN snapshot of CRAN
-  && [ -z "$BUILD_DATE" ] && BUILD_DATE=$(date -I) || true \
+  && [ -z "$BUILD_DATE" ] && BUILD_DATE=$(date -I --date='TZ="America/Los_Angeles"') || true \
   && MRAN=https://mran.microsoft.com/snapshot/$BUILD_DATE \
   && echo "options(repos = c(CRAN = 'https://cran.rstudio.com', MRAN = '$MRAN'))" > /usr/local/lib/R/etc/Rprofile.site \
   && Rscript -e "install.packages(c('RSQLite', 'RMySQL', 'RPostgreSQL'), repo = getOption('repos')[['MRAN']])" \