Create SECURITY.md (#31)

* Create SECURITY.md

* soften tolerance on wet-dry well-balancedness test

---------

Co-authored-by: Andrew Winters <[email protected]>

SECURITY.md

@@ -0,0 +1,30 @@
+# Security Policy
+
+The Trixi.jl development team takes security issues seriously. We appreciate
+all efforts to responsibly disclose any security issues and will make every
+effort to acknowledge contributions.
+
+
+## Supported Versions
+
+The current stable release following the interpretation of
+[semantic versioning (SemVer)](https://julialang.github.io/Pkg.jl/dev/compatibility/#Version-specifier-format-1)
+used in the Julia ecosystem is supported with security updates.
+
+
+## Reporting a Vulnerability
+
+To report a security issue, please use the GitHub Security Advisory
+["Report a Vulnerability"](https://github.com/trixi-framework/TrixiShallowWater.jl/security/advisories/new)
+tab.
+
+We will send a response indicating the next steps in handling your report.
+After the initial reply to your report, we will keep you informed of the
+progress towards a fix and full announcement, and may ask for additional
+information or guidance.
+
+Please report security bugs in third-party modules directly to the person
+or team maintaining the module.
+
+Public notifications of vulnerabilities will be shared in community channels
+such as Slack.

test/test_unstructured_2d.jl

@@ -258,7 +258,8 @@ isdir(outdir) && rm(outdir, recursive = true)
                             ],
                             tspan=(0.0, 2.0),
                             surface_flux=(FluxHLL(min_max_speed_naive),
-                                          flux_nonconservative_fjordholm_etal))
+                                          flux_nonconservative_fjordholm_etal),
+                            atol=1e-10)
         # Ensure that we do not have excessive memory allocations
         # (e.g., from type instabilities)
         let