Disable pylint 2.8 consider-using-with refactoring suggestion (#1244)

Each pygmt.Figure instance has an associated directory that
holds temporary preview PNG and/or PDF figure files. It's
not easy to use a with-statement since TemporaryDirectory
is called in the __init__ of the Figure class, so the pylint
recommendation is simply disabled here.

Author: weiji14

pygmt/figure.py

@@ -79,7 +79,9 @@ class Figure:
 
     def __init__(self):
         self._name = unique_name()
-        self._preview_dir = TemporaryDirectory(prefix=self._name + "-preview-")
+        self._preview_dir = TemporaryDirectory(  # pylint: disable=consider-using-with
+            prefix=f"{self._name}-preview-"
+        )
         self._activate_figure()
 
     def __del__(self):
@@ -375,7 +377,7 @@ def _preview(self, fmt, dpi, as_bytes=False, **kwargs):
             If ``as_bytes=False``, this is the file name of the preview image
             file. Else, it is the file content loaded as a bytes string.
         """
-        fname = os.path.join(self._preview_dir.name, "{}.{}".format(self._name, fmt))
+        fname = os.path.join(self._preview_dir.name, f"{self._name}.{fmt}")
         self.savefig(fname, dpi=dpi, **kwargs)
         if as_bytes:
             with open(fname, "rb") as image: