fpm tests fail if build against toml-f 0.3.1 instead of 0.2.4

[band-a-prend]

Description

Step to reproduce for fpm-0.7.0 release or for fpm from commit-sha=58c7f76cecccf3062e870fab4e066c8719428ee9:

1. Clone fpm repository:
   git clone https://github.com/fortran-lang/fpm.git
2. If use previously cloned repo then delete the build directory: it could contains previously fetched toml-f-0.2.4 and then build process will use it instead of new version of toml-f.
3. Update toml-f from 0.2.4 to 0.3.1 commit-sha:
   sed -i 's/e49f5523e4ee67db6628618864504448fb8c8939/aee54c5a480d623af99828c76df0447a15ce90dc/' fpm.toml
4. Download bootstrap fpm:
   wget https://github.com/fortran-lang/fpm/releases/download/current/fpm.F90
5. Build bootstrap executable:

mkdir -p build/bootstrap
gfortran -J build/bootstrap -o build/bootstrap/fpm fpm.F90

6. Build fpm using bootstraped fpm:
   ./build/bootstrap/fpm build
7. Run tests:
   ./build/bootstrap/fpm test
8. Noticed that results (build with toml-f-0.3.1) differ from results when build with toml-f-0.2.4 ([EXPECTED FAIL]) and have errors ([FAILED]):

...
# Starting invalid-toml ... (2/3)
#      ... invalid-toml [EXPECTED FAIL]
# Message: error: Key 'dependencies' already exists
 --> fpm-invalid-toml.toml:4:2-13
  |
3 | dependencies.fpm.git = "https://github.com/fortran-lang/fpm"
  | ------------ first defined here
4 | [dependencies]
  |  ^^^^^^^^^^^^ key already used
  |
...
# Starting package-simple ... (24/48)
#      ... package-simple [FAILED]
# Message: manifest file syntax error: package name must be composed only of alphanumerics, "-" and "_"  and start with a letter ::"example"
...
# Starting package-wrongexe ... (28/48)
#      ... package-wrongexe [EXPECTED FAIL]
# Message: manifest file syntax error: package name must be composed only of alphanumerics, "-" and "_"  and start with a letter ::"example"
# Starting package-wrongtest ... (29/48)
#      ... package-wrongtest [EXPECTED FAIL]
# Message: manifest file syntax error: package name must be composed only of alphanumerics, "-" and "_"  and start with a letter ::"example"
# Starting package-duplicate ... (30/48)
#      ... package-duplicate [EXPECTED FAIL]
# Message: manifest file syntax error: package name must be composed only of alphanumerics, "-" and "_"  and start with a letter ::"example"
# Starting test-simple ... (31/48)
#      ... test-simple [FAILED]
# Message: manifest file syntax error: test name must be composed only of alphanumerics, "-" and "_"  and start with a letter ::"example"
...
# Starting example-simple ... (39/48)
#      ... example-simple [FAILED]
# Message: manifest file syntax error: example name must be composed only of alphanumerics, "-" and "_"  and start with a letter ::"example"
...
3 test(s) failed!
ERROR STOP 1

Error termination. Backtrace:
#0  0x7f2b24d7ea28 in ???
#1  0x7f2b24d7f674 in ???
#2  0x7f2b24d80e6e in ???
#3  0x5640c20c09f7 in fpm_testing
        at test/fpm_test/main.f90:67
#4  0x5640c20c0a57 in main
        at test/fpm_test/main.f90:5
...
<ERROR> Execution failed for object " fpm-test "
<ERROR>*cmd_run*:stopping due to failed executions
STOP 1

The same tests if build with toml-f-0.2.4:

...
# Starting invalid-toml ... (2/3)
#      ... invalid-toml [EXPECTED FAIL]
# Message: line 4: Duplicate key (dependencies) found
   | [dependencies]
   |--------------^
...
# Starting package-simple ... (24/48)
#      ... package-simple [PASSED]
...
# Starting package-wrongexe ... (28/48)
#      ... package-wrongexe [EXPECTED FAIL]
# Message: Could not retrieve executable from array entry
# Starting package-wrongtest ... (29/48)
#      ... package-wrongtest [EXPECTED FAIL]
# Message: Could not retrieve test from array entry
# Starting package-duplicate ... (30/48)
#      ... package-duplicate [EXPECTED FAIL]
# Message: The program named 'prog' is duplicated. Unique program names are required.
# Starting test-simple ... (31/48)
#      ... test-simple [PASSED]
...
# Starting example-simple ... (39/48)
#      ... example-simple [PASSED]
...

Expected Behaviour

All expected tests are passed and results are the same if build fpm against toml-0.2.4 and toml-0.3.1

Version of fpm

0.7.0, 58c7f76

Platform and Architecture

Gentoo Linux, amd64

Additional Information

No response