[ci] remove pin on tinytex in R CI jobs (#5821)

.ci/test_r_package.sh

@@ -118,6 +118,12 @@ if [[ $OS_NAME == "macos" ]]; then
     fi
 fi
 
+# fix for issue where CRAN was not returning {lattice} when using R 3.6
+# "Warning: dependency ‘lattice’ is not available"
+if [[ "${R_MAJOR_VERSION}" == "3" ]]; then
+    Rscript --vanilla -e "install.packages('lattice', repos = 'https://mran.microsoft.com', lib = '${R_LIB_PATH}')"
+fi
+
 # Manually install Depends and Imports libraries + 'knitr', 'RhpcBLASctl', 'rmarkdown', 'testthat'
 # to avoid a CI-time dependency on devtools (for devtools::install_deps())
 # NOTE: testthat is not required when running rchk

.github/workflows/r_package.yml

@@ -197,9 +197,6 @@ jobs:
         env:
           CTAN_MIRROR: https://ctan.math.illinois.edu/systems/win32/miktex
           TINYTEX_INSTALLER: TinyTeX
-          # pinning to an old version to address breaking changes to paths not being available yet
-          # (ref: https://github.com/r-lib/actions/issues/713#issuecomment-1481293175)
-          TINYTEX_VERSION: '2023.03'
       - name: Setup and run tests on Linux and macOS
         if: matrix.os == 'macOS-latest' || matrix.os == 'ubuntu-latest'
         shell: bash