CI: Pin ghostscript to 9.54.0 in Tests and Dev Tests workflows (#2754)

Author: seisman

.github/workflows/ci_tests.yaml

@@ -106,6 +106,7 @@ jobs:
           create-args: >-
             python=${{ matrix.python-version }}${{ matrix.optional-packages }}
             gmt=6.4.0
+            ghostscript=9.54.0
             numpy=${{ matrix.numpy-version }}
             pandas
             xarray

.github/workflows/ci_tests_dev.yaml

@@ -106,7 +106,7 @@ jobs:
             ninja
             curl
             fftw
-            ghostscript
+            ghostscript=9.54.0
             hdf5
             libblas
             libcblas