Create CITATION.cff

Author: abhro

CITATION.cff

@@ -0,0 +1,15 @@
+cff-version: 1.2.0
+type: software
+title: Spectra.jl
+message: If you use this software, please cite it using the metadata from this file.
+repository-code: 'https://github.com/JuliaAstro/Spectra.jl'
+authors:
+  - given-names: Miles
+    family-names: Lucas
+    email: mdlucas@hawaii.edu
+    orcid: 'https://orcid.org/0000-0001-6341-310X'
+  - name: JuliaAstro
+    email: astro@julialang.org
+    website: 'https://juliaastro.org'
+url: 'https://juliaastro.org/Spectra'
+license: MIT