fix deploy on travis

.travis.yml

@@ -22,7 +22,7 @@ before_install:
   - R -q -e 'if (getRversion() < "3.2" && !requireNamespace("curl")) install.packages("curl")'
   - R -q -e 'remotes::install_github("ropenscilabs/tic", upgrade = "always"); print(tic::dsl_load()); tic::prepare_all_stages()'
   - R -q -e 'tic::before_install()'
-install: R -q -e 'tic::install()'
+install: R -q -e 'tic::install();remotes::install_version("rmarkdown", "1.15")'
 after_install: R -q -e 'tic::after_install()'
 before_script: R -q -e 'tic::before_script()'
 script: R -q -e 'tic::script()'