Add stub maintenance doc

Author: jimhester

.Rbuildignore

@@ -24,3 +24,4 @@ script.R
 ^revdep$
 ^talk$
 \.cache$
+^MAINTENANCE\.md$

MAINTENANCE.md

@@ -0,0 +1,28 @@
+## Current state
+
+## Known outstanding issues
+
+### False positive URL checks for git repositories in the vignettes
+
+If you run `urlchecker::url_check()` on the repo you will see the following false positives.
+
+```
+! Warning: vignettes/motivations.Rmd:363:11 Moved
+git clone https://github.com/r-lib/cpp11.git
+          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+          https://github.com/r-lib/cpp11
+! Warning: vignettes/motivations.Rmd:354:11 Moved
+git clone https://github.com/RcppCore/Rcpp.git
+          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+          https://github.com/RcppCore/Rcpp
+>
+```
+
+These only happen with the urlchecker package, they can be safely ignored and the real CRAN checks will not show them.
+
+
+### Ensure you use `Sys.setenv("CPP11_EVAL" = "true"); devtools::submit_cran()` when submitting.
+
+If you forget to set `CPP_EVAL = "true"` then the vignette chunks will not run properly and the vignettes will not be rendered properly.
+
+## Future directions