meson: adjust nlohmann-json dependency

- Simplify nlohmann-json dependency in meson.build.
- Use consistent dependency variable names (based on Meson style).
- Align wrap file name with meson wrapdb choice for the project.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I2e893fd8c300b36a16d704f2002bb966a6e52ce4
diff --git a/subprojects/nlohmann.wrap b/subprojects/nlohmann_json.wrap
similarity index 62%
rename from subprojects/nlohmann.wrap
rename to subprojects/nlohmann_json.wrap
index 477e844..3745380 100644
--- a/subprojects/nlohmann.wrap
+++ b/subprojects/nlohmann_json.wrap
@@ -1,6 +1,6 @@
 [wrap-git]
-url = https://github.com/nlohmann/json
 revision = HEAD
+url = https://github.com/nlohmann/json.git
 
 [provide]
 nlohmann_json = nlohmann_json_dep