add .github/ with Contributing, Funding, Issue and PR hints

Author: eddelbuettel

.github/CONTRIBUTING.md

@@ -0,0 +1,9 @@
+
+### Contributing to Rcpp
+
+Please see the file [Contributing](https://github.com/RcppCore/Rcpp/blob/master/Contributing.md) for details on
+
+- how to report an issue: a [Minimally Complete (and) Verifiable Example (MCVE)](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) helps a lot;
+- how to submit a pull request: post an issue first, get consensus about _what_ and _how_;
+- how to follow our (informal) coding style: simply do as other files do and do not invent a new style;
+- how to be nice and add [ChangeLog](https://github.com/RcppCore/Rcpp/blob/master/ChangeLog) and [NEWS.Rd](https://github.com/RcppCore/Rcpp/blob/master/ChangeLog).

.github/FUNDING.yml

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+github: eddelbuettel

.github/ISSUE_TEMPLATE.md

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+
+### Reporting an Issue
+
+_Make use of the *Preview* tab just above!_
+
+#### Before filing an issue with Rcpp, please ensure that you
+
+- searched the mailing list archives for the
+  [rcpp-devel](https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel) list for the question I want to
+  ask about; you can do this at at Google with the `site:` qualifier as in this simple example:
+  `site:lists.r-forge.r-project.org rcpp-devel how do I declare a const vector`;
+
+- searched [StackOverflow](https://stackoverflow.com/) under the `[rcpp]` tag by searching _e.g._ via `[rcpp] how do I sample a vector`;
+
+- searched the existing [GitHub issues](https://github.com/RcppCore/Rcpp/issues) which too can be search among open and
+  (importantly!) closed ones;
+
+- read the [Contributing](https://github.com/RcppCore/Rcpp/blob/master/Contributing.md) page for details on preferred
+  reporting and style;
+
+#### If you have the above, remove the text above and provide
+
+- A [`Minimally Complete and Reproducible Example`](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example)
+
+- The output of `sessionInfo()` plus relevant information about the C++ compiler used not added by R

.github/PULL_REQUEST_TEMPLATE.md

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+
+### Pull Request Template for Rcpp
+
+Please explain the changes you want to apply to Rcpp, preferably in an issue ticket **before** you create a pull
+request. See the file [Contributing](https://github.com/RcppCore/Rcpp/blob/master/Contributing.md) and the other
+templates for details.
+
+#### Checklist
+
+- [ ] Code compiles correctly
+- [ ] `R CMD check` still passes all tests
+- [ ] Prefereably, new tests were added which fail without the change
+- [ ] Document the changes by file in [ChangeLog](https://github.com/RcppCore/Rcpp/blob/master/ChangeLog)

ChangeLog

@@ -1,5 +1,8 @@
 2019-11-10  Dirk Eddelbuettel  <edd@debian.org>
 
+	* .github/: Add files CONTRIBUTING.md, FUNDING.yml, ISSUE_TEMPLATE.md
+	and PULL_REQUEST_TEMPLATE.md
+
 	* inst/include/Rcpp/config.h: Correct RCPP_VERSION and
 	RCPP_DEV_VERSION to 1.0.3